After disclosing last week that starting cornerback Leodis McKelvin had suffered a setback in his recovery from an ankle injury, Buffalo Bills head coach Rex Ryan took that synopsis a step further on Thursday, casting doubt on McKelvin's availability for the start of the regular season.

"We thought everything was on track, and with a lot of these types of injuries you have some setbacks, and he experienced a setback," Ryan said. "He will play this season, but when he's going to be available, I'm not real sure."

McKelvin has been present for camp practices at St. John Fisher, but he is wearing a protective boot on the ankle that he broke on November 13 last year. He had surgery last fall to fix the break, and had recovered enough to do some on-field work during spring workouts, but the aggravated injury has forced him onto crutches and into golf carts at camp so far.

If McKelvin can't suit up for the Bills' Week 1 date with the Indianapolis Colts, rookie second-round pick Ronald Darby - who has been one of the more noticeably positive story lines coming out of the Bills' first six camp practices - would step into the starting lineup for one of the NFL's best defenses. It would be a tall task for a rookie, even one with Darby's raw talent, to hold up against an offense featuring one of the league's best quarterbacks, Andrew Luck, and a very formidable receiving duo in T.Y. Hilton and Andre Johnson.