Injuries knock champions Cody Garbrandt and Michael Bisping off UFC 213 fight card

Injuries to two UFC champions has resulted in a watered-down UFC 213 card, the organization said Tuesday.

While the women’s bantamweight title fight between champion Amanda Nunes and top contender Valentina Shevchenko remains intact as the main event, the new co-main event is a middleweight bout between contenders Yoel Romero and Robert Whittaker.

Despite efforts to include one or both on the marquee International Fight Week card July 8 at T-Mobile Arena in Las Vegas, middleweight champion Michael Bisping and new bantamweight champion Cody Garbrandt will not be on the card.

The unbeaten Garbrandt has begun receiving stem-cell injections to treat his back, which he injured in training for a planned first title defense against former champion and former training partner T.J. Dillashaw.

Garbrandt “needs four weeks to rest after the shots. That puts him into July,” UFC President Dana White told The Times Tuesday in a text message.

Since reports of Garbrandt’s injury emerged, Dillashaw has pushed for a shot at flyweight champion Demetrious Johnson, and White said he’s working to make that fight happen atop a possible pay-per-view card in August near Johnson’s hometown in Seattle.

“TJ wants the DJ fight and I love it,” White said. “Great fight for the best [pound-for-pound] fighter on Earth.”

Johnson tied UFC legend Anderson Silva in April with his 10th consecutive successful title defense when he dominated Wilson Reis, but getting the record to himself would require winning his stiffest test yet.

Dillashaw (15-3), a former Cal State Fullerton wrestler, held the bantamweight belt for more than 18 months before losing it to Dominick Cruz, who has also defeated Johnson. Dillashaw has won twice since and built anticipation for the Garbrandt bout by coaching against him in this season’s “The Ultimate Fighter” reality television series.

Middleweight champion Bisping of England has an injured knee that will keep him from fighting Cuba’s Romero, who emerged as a replacement opponent in place of former welterweight champion Georges St-Pierre.

White said St-Pierre will fight at a date to be determined, hopefully later this year.

Now, Romero (12-1), coming off a victory over former champion Chris Weidman, will meet heavy-handed Robert Whittaker (19-4) for the interim middleweight title and a shot at Bisping when he returns to health.

lance.pugmire@latimes.com

Twitter: @latimespugmire