Golden Boy Promotions CEO Oscar De La Hoya warns that former IBF middleweight world champion David Lemieux (39-4, 33 KOs) can not afford another defeat, when he faces Ireland's Gary “Spike” O’Sullivan (28-2, 20 KOs).

The contest will take place on September 15, at the T-Mobile Arena in Las Vegas, Nevada.

The card will be headlined by the middleweight rematch between Canelo Alvarez and WBC, IBO, WBA world champion Gennady Golovkin. HBO Pay-Per-View will carry both contests.

De La Hoya's company promotes both Lemieux and O'Sullivan.

Lemieux, who has superstar status in his country of Canada, has lost two of his last seven. He was dominated over twelve rounds last December, by WBO world champion Billy Joe Saunders.

And when he came back to the ring in May of this year, he wasn't overly impressive in winning a twelve round unanimous decision over Karim Achour - and Lemieux struggled with his weight and was unable to make the middleweight limit - as he was two pounds above the weight class.

A loss to O'Sullivan could very well finish Lemieux's run as a top-tier fighter - which is why De La Hoya cautions that another loss would be catastrophic for the Canadian's career.

“Lemieux-O’Sullivan is a great fight, a lot of action, but it’s a very important fight for David Lemieux,” De La Hoya told Yahoo Sports. “It’s kind of make-or-break for him. He needs this one.”

Lemieux has no problem with De La Hoya's comments, because he realizes that Golden Boy wants to match him against the bigger names of the weight class - and suffering another loss would severely set him back.

“They expect a lot from me and it’s all good,” Lemieux said. “I know what I’m worth and I know what I’ll bring to the table on Sept. 15. It’s going to be a beautiful victory. I’m in great shape. I’m coming down for business. I’m coming down for big names. The first big name is going to be Gary O’Sullivan, and then we’re going to head up to some who are the real deal.”