Foster's status was uncertain due to a knee injury that forced the two-time Pro Bowler to miss Friday's practice.
But after testing his knee during pregame warm-ups, Foster joined the Texans on the field for their opening possession and was their primary ball carrier throughout the contest.
"He was fine," Texans coach Gary Kubiak said. "I think he carried it 25 times. Arian was OK. He was fine going into the game. That's part of procedure -- if you don't practice on Friday, you become a game-time decision."
Despite struggling early, Foster rushed for 79 yards and two touchdowns on 26 carries.
"We got the win, so that's the most important thing," Foster said. "But I felt like I played smooth."
Foster is coming off his second consecutive 1,200-yard season for the Texans, who came within a win of reaching the AFC title game last season before losing to the Ravens.
Foster became the first player to rush for 100 yards against Baltimore in the postseason with 132 yards.
Foster, a fourth-year veteran, followed a career-high 1,616-yard, 16-touchdown effort in 2010 with 1,224 yards and 10 TDs last season.