Reed appeared to be favoring his left leg as he gingerly walked toward the sideline, and he later was carted to the locker room. The Texans already were down a linebacker because starter Tim Dobbins was inactive because of a shoulder problem.
Reed, a second-year pro, entered the game with 2.5 sacks in 10 games. He had six sacks as a rookie last season.
The Texans also lost linebacker Bradie James and offensive tackle to Derek Newton to respective hamstring and knee injuries during the second half.
The Associated Press contributed to this report.