Welterweight contender Sean Strickland has withdrawn from a showdown against Tim Means on this month’s UFC 202 card and promotional officials have been scrambling in an effort to find a replacement.

Strickland suffered an injury to his knee in training and there is no timetable on when he’ll be able to return to action. MMAjunkie first reported the news on Friday.

Means has been preparing for his return to the Octagon ever since he was suspended when USADA found him in violation of its anti-doping policy. “The Dirty Bird” was slated to meet Donald Cerrone at UFC Fight Night 83 but was forced off the bill when the USADA investigation came to light. Means protested the violation and was able to reduce a potential two-year suspension down to six months when he proved that the supplements he ingested were tainted.

The mega event goes down Aug. 20 in Las Vegas in the new T-Mobile Arena, the site of the blockbuster UFC 200 card. The grudge rematch between reigning featherweight champion Conor McGregor and Nate Diaz will anchor the festivities, though they will meet in a non-title bout at welterweight.

Fan favorite Donald Cerrone will lock horns with Rick Story and Anthony Johnson will oppose Glover Teixeira in a pivotal light heavyweight affair. Cody Garbrandt will take on Japanese star Takeya Mizugaki as well.

UFC 202 will be brought to fight fans live on UFC Fight Pass, Fox Sports 1 and pay-per-view.