Diaz to fight Cruz on Lomachenko-Rigondeauz undercard

Christopher Diaz has a new opponent for his ESPN-televised fight on the undercard of the much-anticipated Vasyl Lomachenko-Guillermo Rigondeaux junior lightweight world title fight on Saturday night.

Junior lightweight up-and-comer Diaz was due to face Casey Ramos in a 10-round bout in the second of fight on the four-fight telecast (9 p.m. ET) at the Theater at Madison Square Garden in New York. However, Ramos withdrew from the fight on Friday night and was replaced over the weekend by Bryant "Pee Wee" Cruz, Top Rank vice president Carl Moretti told ESPN on Monday.

Moretti said he was not sure why Ramos (24-1, 6 KOs), 28, of Austin, Texas, pulled out of the fight. "We have not been presented with a reasonable or logical reason why Ramos is out," Moretti said. "I just know he is not getting on a plane to come to New York for the fight, and he's out. (Top Rank matchmaker) Brad (Goodman) did all the work to get the new fight done quickly."

Diaz (21-0, 13 KOs), 23, of Puerto Rico, will be fighting for the first time since April, a layoff caused by a hand injury. Cruz (18-2, 9 KOs), 27, of Port Chester, New York, lost to Ryan Martin by eighth-round knockout in a lightweight bout in the Madison Square Garden main arena on March 18 on the Gennady Golovkin-Daniel Jacobs pay-per-view undercard, but he bounced back for a third-round knockout win against Angel Luna on Nov. 18.

"Considering Cruz is coming off a win only three weeks ago and he's still in shape -- and he didn't hesitate to take the fight with Diaz -- we expect a highly competitive fight on Saturday night," Moretti said.