Title bout between champ Badou Jack, challenger George Groves postponed

The fight between super middleweight titlist Badou Jack and mandatory challenger George Groves, scheduled to take place on Aug. 22 in Las Vegas and be televised on Showtime, has been postponed.

Neither fighter is injured, but Showtime offered no explanation for the postponement. Mayweather Promotions CEO Leonard Ellerbe, Jack's promoter and promoter of the card, did not return messages from ESPN.com seeking comment.

"It's not happening on that date," Showtime spokesman Chris DeBlasio told ESPN.com.

Speculation is that the fight will simply be delayed for three weeks and take place on Sept. 12 on the undercard of pound-for-pound king Floyd Mayweather's next fight. DeBlasio declined to comment on that possibility.

Mayweather's next fight, which is supposed to be at the MGM Grand in Las Vegas, could be on Showtime PPV or on CBS. Former two-time welterweight titlist Andre Berto (30-3, 23 KOs) is considered the leading candidate to get the fight even though he is just 3-3 in his past six fights and considered a long-faded fighter.

Mayweather (48-0, 26 KOs) has said repeatedly that his Sept. 12 fight will be the last of his career as he closes out his six-fight contract with Showtime/CBS. He is already in training camp in Las Vegas even though no opponent has been announced.

There was a meeting between network executives on Tuesday morning to discuss whether Mayweather's fight would be on CBS or pay-per-view, but no decision was made, a source with knowledge of the meeting told ESPN.com.

Mayweather, the welterweight world champion, is coming off his May 2 unanimous decision victory against Manny Pacquiao in the biggest pay-per-view fight in history (4.4 million buys) and largest-grossing fight ever, for which Mayweather earned around a record $220 million.

Ellerbe and Team Sauerland, which promotes Groves, made a deal a couple of months ago for the fight and avoided a purse bid. Jack (19-1-1, 12 KOs), 31, a native of Sweden who lives and trains in Las Vegas, scored a mild upset when he won a majority decision and the belt from Anthony Dirrell on April 24 in Chicago.

The win was Jack's third in a row since suffering a first-round knockout loss in a major upset to Derek Edwards in February 2014.

Groves (21-2, 16 KOs), 27, of England, will be getting his third shot at a 168-pound world title. He was stopped in back-to-back fights in 2013 (controversially) and 2014 (cleanly) challenging then-titleholder Carl Froch, his countryman, in a pair of major British fights, the second of which took place before a crowd of some 80,000 at Wembley Stadium in London.

Since the two losses, Groves has won two fights in a row, including capturing the European title.