Bob Arum believes Manny Pacquiao is risking lasting damage by continuing to fight into his 40s.
The fighters will meet at the MGM Grand with Manny Pacquiao favoured to take the title from Keith Thurman.
The human cranium thins out as you get older and fighters are more susceptible to brain damage.
The 40-year-old Filipino multiple world champion was quicker and more accurate as he took his career record to 61-7-2.
Filipino boxing star Manny Pacquiao and former world welterweight champion Adrien Broner will soon announce details about their upcoming bout to be held in Las Vegas.
In his first US bout since November 2016, Manny Pacquiao will fight Adrien Broner.
Victor Ortiz would have fought John Molina Jr.
In a post on Instagram, former world welterweight champion Floyd Mayweather said he will come out of retirement to fight Manny Pacquiao once more.
Shawn Porter and Danny Garcia will take to the ring with the vacant World Boxing Council welterweight title on the line.
Lucas Matthysse announced his retirement just two weeks after a knockout loss to Filipino Manny Pacquiao.
WBA welterweight champion says Manny Pacquiao is a great fighter, but that the Filipino hasn't fought him yet.
Jeff Horn retained the title after Gary Corcoran conceded in the 11th round.