"It's uncertain whether Bob Sanders will be available when the Indianapolis Colts host the Houston Texans on Sunday at Lucas Oil Stadium.

The veteran safety missed his second straight practice Thursday after suffering an elbow injury in last weekend's win over San Francisco.

"He's getting it evaluated," said coach Jim Caldwell, who was unable to elaborate on the injury's severity.

Caldwell noted the injury did not keep Sanders from finishing the 49ers game but became an issue "a little while later."

If Sanders is out, Melvin Bullitt is back in the starting lineup. As has been the case whenever Sanders has missed time -- he was out for the first five games of the season while completing his rehab from offseason knee surgery -- Bullitt will be ready."