CHARLOTTE – Head coach Ron Rivera, already aware that a couple of defensive linemen aren't likely to play against the Indianapolis Colts, is now hoping that the anchor of the offensive line won't join them on the sideline.

Center Ryan Kalil missed practice Thursday with an ankle injury that has Rivera "a little bit" concerned about his availability for Monday Night Football. Rivera reaffirmed that defensive end Mario Addison (shoulder) won't play against the Colts and said defensive tackle Dwan Edwards (ankle) probably wouldn't play.

Rivera is taking more of a wait-and-see approach with linebacker Shaq Thompson (knee), who like Edwards could miss a second consecutive game, and with Kalil.

"Those guys stayed in and did extra work," Rivera said. "I know specifically with Shaq, they got him on the underwater treadmill to get him going. We'll see how he is tomorrow morning."

Rivera said he didn't know how Kalil, who didn't miss any plays in last Sunday night's victory over the Philadelphia Eagles, suffered his injury.

"They told me he twisted it. I didn't even notice anything watching the tape," Rivera said. "We're trying to be careful, just getting it to calm down and get the swelling out."

Rivera said that seven-year veteran Fernando Velasco, who filled in when Kalil missed his one play all season two weeks ago at Seattle, would take over for Kalil if he can't play.

"He's done a nice job," Rivera said. "He's taking all the reps right now, with Chris Scott taking the backup reps."