ST. LOUIS -- Danario Alexander signed with the St. Louis Rams in late August as something of a long-term project, given he still was rehabbing from a fourth operation on his left knee.

Injuries at wide receiver have forced the Rams to alter that timetable, and the former Missouri star wide receiver might make his NFL debut against the San Diego Chargers on Sunday.

Alexander was promoted to the roster from the practice squad earlier this week and was confident after practice Wednesday that the knee was strong enough. He's ready to play special teams if that's where the Rams (2-3) need him.

"I anticipate playing," Alexander said. "I'm practicing like I will be. We'll see Sunday."

Rams coach Steve Spagnuolo was noncommittal about Alexander's chances for playing this week. But he said the 6-foot-5, 220-pounder deserved this shot.

"He knew he had a little bit of a road to overcome," Spagnuolo said. "It was a health issue, but he's kind of worked right in there. I know the guys like him. He's worked hard."

Teammates razzed Alexander for several minutes, producing embarrassed smiles from the wide receiver, as media crowded around his locker stall around the corner from where players on the active roster dress.

"I'm very excited," Alexander said. "I'm looking forward to the opportunity that they gave me."

Alexander led the nation with 1,781 yards receiving and was all-Big 12 his senior season at Missouri. He wasn't drafted after getting injured before the Senior Bowl but got a four-year contract that included a modest bonus.

After signing with St. Louis on Aug. 22, Alexander lifted weights four times a week and had treatment five times weekly to build strength in a leg that had atrophied since surgery. He's been impressive lately with scout team work on the practice squad, earning the promotion at a position where the Rams had an unsung cast even before Mark Clayton was placed on injured reserve earlier this week with a torn patella tendon in his right knee.

"He's made some spectacular catches," quarterback Sam Bradford said. "He's a big body, he's got a lot of speed. So I'm looking forward to getting him in the rotation and developing a chemistry with him."

Donnie Avery, the leading receiver last year, went on IR in the preseason with a knee injury.