Arian Foster went down in a heap without taking a hit.
Foster injured his right Achilles tendon late in the fourth quarter of Houston's 44-26 loss at Miami on Sunday. Texans coach Bill O'Brien said he didn't know the severity of the injury, but added "it obviously didn't look good." If Foster tore his Achilles, his season is over.
Foster was starting to run a pass pattern off pre-snap motion when he fell to the ground and grabbed his leg. He was helped off the field by teammates and training staff.
Foster hasn't played a full season since 2012. The four-time Pro Bowl pick missed eight games after having back surgery in 2013, sat out three games last year and three more this season. He's battled groin, hamstring and calf injuries.
In St. Louis, Johnny Football made his first appearance since Week 2 after Josh McCown hurt his right arm late in Cleveland's 24-6 loss to the Rams.
McCown left favoring his right arm and Manziel entered for his first action since he was questioned Oct. 12 by police in Avon, Ohio, after the 2012 Heisman Trophy winner argued with his girlfriend while driving on a highway.
In other injury news:
-- Lions QB Matthew Stafford had X-rays on his left hand after the game.
-- Jets C Nick Mangold left the game late in the fourth quarter after hurting his neck when he collided with a defensive lineman.
-- Colts WR Phillip Dorsett, a 2015 first-round pick, injured his left ankle in the first half.
-- Redskins LB Ryan Kerrigan injured his hand in the first half and didn't return. In that game, Buccaneers WR Louis Murphy grabbed his right knee at the end of an 18-yard catch in the first quarter and didn't return.
-- Falcons WR Leonard Hankerson left in the third quarter with a hamstring injury and S William Moore went out with a groin injury. Also in that game, Titans CB Jason McCourty came out after a hamstring injury and C Andy Gallik is in concussion protocol.
-- Bills LB A.J. Tarpley left the game with a possible concussion.