Manny Pacquiao through the years

Pacquiao’s professional boxing career started in 1995 and he boxed primarily in the Philippines until 2001. In his 2001 debut in the United States against Lehlohonolo Ledwaba of South Africa, Pacquiao won by TKO in six rounds.  (Laura Rauch / Associated Press)

Before facing Mexico’s Erik Morales in March 19, 2005, in Las Vegas, Pacquiao had not lost since September 1999. Morales won by unanimous decision to take the WBC international super featherweight title.  (Eric Jamison / Associated Press)

Ten months later, Pacquiao faced Erik Morales again. Pacquiao knocked Morales out in the 10th round. It was the first time Morales was knocked out in his boxing career.   (Jed Jacobsohn / Getty Images)

Pacquiao trades punches with David Diaz during their WBC lightweight championship boxing match June 28, 2008, in Las Vegas. Pacquiao won by knockout in the ninth round.  (Eric Jamison / Associated Press)

Pacquiao celebrates after knocking out Oscar de la Hoya -- nicknamed “The Golden Boy” -- in the eighth round in the highly anticipated match on Dec. 6, 2008. De La Hoya retired shortly after the loss.  (Wally Skalij / Los Angeles Times)

Pacquiao knocked out British boxer Ricky Hatton in the second round of the junior welterweight title fight on May 2, 2009. Hatton retired after the match. Pacquiao became the second boxer in history to win six titles from six different weight categories.  (Wally Skalij / Los Angeles Times)

Supporters cheer at a celebration event in Los Angeles after Pacquiao defeated Ricky Hatton. In 2008, Pacquiao received the Philippines Legion of Honor for bringing honor to his country from the boxing ring.  (Ringo H.W. Chiu / For The Times)

Pacquiao is mobbed by supporters during his campaign trip in the southern Philippines in 2010. Pacquiao ran for a congressional seat in his home province of Sarangani and was elected in 2010 and 2013.  (Bullit Marquez / Associated Press)

On June 6, 2012, Pacquiao lost to American Timothy Bradley on a split decision at the WBO welterweight championship match. It was Pacquiao’s first loss since his loss to Erik Morales in 2005.  (Kevork Djansezian / Getty Images)

Referee Kenny Bayless, center, holds back Juan Manuel Marquez, right, as Pacquiao lies face down and knocked out in the sixth round of a match in December 2012 at the MGM Grand in Las Vegas. It was the first time Pacquiao lost consecutive matches in his 18-year career.  (John Gurzinski / AFP/Getty Images)

Philippine boxer Manny Pacquiao throws out the first pitch before a game between the Dodgers and Washington Nationals at Dodger Stadium on Sept. 1, 2014.  (Gus Ruelas / Associated Press)

Two years after his loss to Timothy Bradley, Pacquiao squared off with Bradley again on April 12, 2014, for the WBO welterweight title. Pacquiao won in a unanimous decision, taking back his welterweight title.  (Joe Klamar / AFP/Getty Images)

Manny Pacquiao, right, punches Chris Algieri during their welterweight title fight at The Venetian in Macao on Sunday. Pacquiao won in a 12-round decision.  (Xaume Olleros / AFP/Getty Images)

Manny Pacquiao, right, knocks down Chris Algieri during their welterweight title fight at The Venetian in Macao on Sunday.  (Chris Hyde / Getty Images)