INDIANAPOLIS -- The Indianapolis Colts could be shorthanded in the secondary Sunday when they play the Cleveland Browns.

Safety Mike Adams and cornerback Vontae Davis missed practice for the second straight day because of back and concussion problems, respectively.

Defensive coordinator Greg Manusky said Thursday that he believes Davis will be able to play Sunday. The veteran cornerback still has to go through the NFL's strict concussion protocol before he'll be cleared to play.

If Davis and Adams don't play, the Colts will likely start Darius Butler and LaRon Landry at cornerback and safety against the Browns.

Here's the rest of the Colts' injury report:

Did not practice: Return specialist Josh Cribbs (knee), center Jonotthan Harrison (illness), offensive tackle Xavier Nixon (foot), linebacker Andy Studebaker, guard Hugh Thornton (knee)

Limited practice: Guard Lance Louis (illness), defensive lineman Cory Redding (knee), linebacker Erik Walden (knee)