Bantamweight titlist Joseph Agbeko's mandatory defense against William Gonzalez, already postponed three times, was called off for the fourth time on Monday.

This time the reason is because Agbeko, of Ghana, contracted malaria while training in Africa.

They were scheduled to meet on the untelevised undercard of the Nate Campbell-Joan Guzman lightweight title bout at the Beau Rivage Resort & Casino in Biloxi, Miss., on Saturday night (Showtime, 9 ET/PT).

According to promoter Don King, Agbeko first became ill in mid-August. He had a fever and visited a hospital Aug. 14 in Ghana, where he was treated and released. Although he contracted a mild form of the disease, Agbeko responded to medication and was later deemed to be non-contagious. However, Agbeko said he was not fit to fight Saturday.

"I wanted to fight but I'm just not strong enough to enter a world championship boxing match," Agbeko, 28, said in a statement. "I tried my best to recover in time to fight my mandatory challenger William Gonzalez in Biloxi, but I now agree with the doctors that I can't be ready by then."

According to King's office, Agbeko saw Dr. Allan Fields of the Florida boxing commission on Friday.

"He appears to be regaining his strength," Fields said in a statement. "He should complete his treatment and be able to resume training in two to three weeks. If all goes well, he could be able to participate in a match by October."

Agbeko (25-1, 22 KOs) claimed a vacant title last September, knocking out former junior bantamweight titlist Luis Perez in the seventh round in Sacramento, Calif. But he has not fought since as his first defense against Nicaragua's Gonzalez (21-2, 19 KOs) was postponed multiple times, including from an Aug. 2 card because of Gonzalez's issues obtaining a visa.

"I look forward to being back in the ring defending my title," Agbeko said. "I want my fans to know I'm doing fine and will have a beautiful performance for them to see very soon."

The rest of the card will go on as scheduled, with Campbell defending his three title belts against Guzman, a former junior lightweight titleholder moving up in weight, in the main event. Junior welterweight titlist Timothy Bradley (22-0, 11 KOs) makes his first defense against Edner Cherry (24-5-2, 12 KOs) in the co-feature.

In another notable bout on the card, although not part of Showtime's telecast, Hector Velasquez (50-11-2, 35 KOs) faces Elio Rojas (19-1, 13 KOs) in a featherweight elimination bout.