Clark was injured in the second quarter after trying unsuccessfully to make a catch. He left with two receptions for 21 yards.
Already minus Peyton Manning all season because of neck surgery, the winless Colts could be without their top two tight ends. Clark and Brody Eldridge (hand) both left early in a 31-7 loss to Atlanta and Colts coach Jim Caldwell provided no updates after the game.
Indianapolis (0-9) has lost five straight home games for the first time since 2001 and is on the cusp of falling to 0-10 for the first time since 1997. It was the Colts' worst defeat at home since a 31-3 loss to Seattle on Sept. 14, 1997, the year before Manning arrived.
Information from The Associated Press was used in this report.