Michael Katsidis of Australia bleeds from a cut under his eye during a WBA interim lightweight title fight against Robert Guerrero of the U.S. at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis (L) of Australia takes a punch from Robert Guerrero of the U.S. during their WBA interim lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero (L) of the U.S. battles with Michael Katsidis of Australia during their WBA interim lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada on April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero (C) of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. celebrates his victory over Michael Katsidis of Australia for the vacant interim WBA lightweight title at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis of Australia (L) gets punched by Robert Guerrero of the U.S. during their WBA interim lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus(UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero of the U.S. (L) lands a punch on Michael Katsidis of Australia during their WBA interim lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada April 9, 2011. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING IMAGES OF THE DAY) 

Lightweight boxers Robert Guerrero (L) of the U.S. and Michael Katsidis of Australia face off during an official weigh-in at the MGM Grand Garden Arena in Las Vegas, Nevada April 8, 2011. The boxers will fight for a vacant WBA and interim WBO lightweight title at the arena on April 9. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxers Robert Guerrero (L) of the U.S. and Michael Katsidis of Australia pose during an official weigh-in at the MGM Grand Garden Arena in Las Vegas, Nevada April 8, 2011. The boxers will fight for a vacant WBA and interim WBO lightweight title at the arena on April 9. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis of Australia flexes on the scale during an official weigh-in at the MGM Grand Garden Arena in Las Vegas, Nevada April 8, 2011. Katsidis will fight Robert Guerrero of the U.S. for a vacant WBA and interim WBO lightweight title at the arena on April 9. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Robert Guerrero of the U.S. flexes on the scale during an official weigh-in at the MGM Grand Garden Arena in Las Vegas, Nevada April 8, 2011. Guerrero will fight Michael Katsidis of Australia for a vacant WBA and interim WBO lightweight title at the arena on April 9. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis of Australia speaks during a news conference at the MGM Grand Resort in Las Vegas, Nevada April 7, 2011. Katsidis will fight Robert Guerrero of the U.S. for vacant interim WBA and WBO lightweight titles at the MGM Grand Garden Arena on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero (L) of the U.S. and Michael Katsidis of Australia pose during a news conference at the MGM Grand Resort in Las Vegas, Nevada April 7, 2011. The boxers will fight for vacant interim WBA and WBO lightweight titles at the MGM Grand Garden Arena on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Robert Guerrero (L) of the U.S. and Michael Katsidis of Australia pose during a news conference at the MGM Grand Resort in Las Vegas, Nevada April 7, 2011. The boxers will fight for vacant interim WBA and WBO lightweight titles at the MGM Grand Garden Arena on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero of the U.S. smiles during a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero of the U.S. hits a speed bag during a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero of the U.S. is shown after a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero of the U.S. is reflected in a mirror as he hits a heavy bag during a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero of the U.S. shadow boxes during a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Featherweight boxer Robert Guerrero (L) and middleweight boxer James Kirkland, both of the U.S., pose during a media workout in Las Vegas, Nevada March 29, 2010. Guerrero will fight Michael Katsidis of Australia for a vacant WBA interim title at the MGM Grand Garden Arena in Las Vegas on April 9. Kirkland will fight former champion Nobuhiro Ishida of Japan on the same card. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis (L) of Australia takes a punch from Juan Manuel Marquez of Mexico during their WBA/WBO lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Mark Damon (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis of Australia is treated in his corner between rounds during his fight against WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. Marquez retained his titles with a ninth-round TKO. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico lands a punch on Michael Katsidis of Australia during their title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico lands a punch on Michael Katsidis of Australia during their title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (C) of Mexico poses with boxing promoter Oscar De La Hoya (L) and members of his camp after defeating Michael Katsidis of Australia in a title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Michael Katsidis of Australia takes drink in his corner after losing his WBA/WBO lightweight title fight to Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. Marquez retained his titles with a ninth round TKO. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Juan Manuel Marquez (L) of Mexico lands a punch on Michael Katsidis of Australia during their WBA/WBO lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Juan Manuel Marquez (R) of Mexico falls onto the canvas after taking a punch from Michael Katsidis of Australia in the third round of their WBA/WBO lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. Marquez came back to win with a ninth-round TKO. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING IMAGES OF THE DAY) 

Michael Katsidis of Australia stands in his corner after losing his WBA/WBO lightweight title fight to Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. Marquez retained his titles with a ninth round TKO. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING HEADSHOT) 

Juan Manuel Marquez (L) of Mexico punches Michael Katsidis of Australia during a WBA/WBO lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. Marquez retained his titles with a 9th round TKO. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico celebrates his victory over Michael Katsidis of Australia during a title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Mark Damon (UNITED STATES - Tags: SPORT BOXING) 

Juan Manuel Marquez (L) of Mexico connects on Michael Katsidis of Australia during a WBA/WBO lightweight title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Mark Damon (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico celebrates his victory over Michael Katsidis of Australia during a title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Mark Damon (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico celebrates his victory over Michael Katsidis of Australia during a title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico celebrates his victory over Michael Katsidis of Australia during a title fight at the MGM Grand Garden Arena in Las Vegas, Nevada, November 27, 2010. REUTERS/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis of Australia stretches during a workout for the media in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis of Australia jumps rope during a workout for the media in Las Vegas, Nevada, November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis of Australia stretches during a workout for the media in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Manager/trainer Brendon Smith watches as interim WBO lightweight champion Michael Katsidis of Australia works out in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis of Australia jumps rope during a workout for the media in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis of Australia smiles during an interview in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING HEADSHOT) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico shadow boxes during a workout for the media in Las Vegas, Nevada November 24, 2010. Marquez will defend his title against interim WBO champion Michael Katsidis of Australia at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico smiles during an interview in Las Vegas, Nevada November 24, 2010. Marquez will defend his title against interim WBO champion Michael Katsidis of Australia at the MGM Grand Garden Arena in Las Vegas Saturday, November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING HEADSHOT) 

Interim WBO lightweight champion Michael Katsidis (R) of Australia warms up before a workout as manager/trainer Brendon Smith watches in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Interim WBO lightweight champion Michael Katsidis (R) of Australia chats with manager/trainer Brendon Smith before a workout for the media in Las Vegas, Nevada November 24, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena in Las Vegas November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico shadow boxes during a workout for the media in Las Vegas, Nevada November 24, 2010. Marquez will defend his titles against interim WBO champion Michael Katsidis of Australia at the MGM Grand Garden Arena in Las Vegas on November 27. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez of Mexico attends a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Marquez will defend his titles against Michael Katsidis of Australia at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis of Australia poses next to the statue of MGM's lion mascot during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico and Michael Katsidis of Australia pose next to the statue of MGM's lion mascot during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis, who holds the interim WBO title, will take on Marquez at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico acknowledges fans pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Marquez will defend his titles against Michael Katsidis of Australia at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis of Australia listens during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico greets a fan as he arrives for a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Marquez will defend his titles against Michael Katsidis of Australia at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis (L) of Australia listens to manager/trainer Brendon Smith during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis of Australia smiles during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

Lightweight boxer Michael Katsidis of Australia speaks during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on WBA/WBO lightweight champion Juan Manuel Marquez of Mexico at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING) 

WBA/WBO lightweight champion Juan Manuel Marquez (L) of Mexico faces off with Michael Katsidis of Australia during a pre-fight press conference in the lobby of the MGM Grand Resort in Las Vegas, Nevada November 23, 2010. Barely a month after the death of his older brother, Katsidis will take on Marquez at the MGM Grand Garden Arena on Saturday. REUTERS/Las Vegas Sun/Steve Marcus (UNITED STATES - Tags: SPORT BOXING)