Davis, the team's top cornerback, left Sunday's game against the Steelers in the first quarter and did not return.
Pittsburgh won the game, 51-34. Ben Roethlisberger completed 81.6 percent of his passes while throwing for 522 yards and six touchdowns.
Davis, 26, is in his third season with the Colts after being acquired in a preseason trade with the Dolphins in 2012. He has started 32 consecutive games for Indianapolis, dating back to 2012.
The Colts lead the AFC south with a 5-3 record. Their next game is against the Giants on Nov. 3, a Monday night game.
- Dan Gartland