HOUSTON -- Texans running back Arian Foster is not sure if he'll be able to play in Sunday's opener against Indianapolis because of his hamstring injury.
Foster, the 2010 NFL rushing champion, hurt his left hamstring early in training camp, then aggravated it in the preseason game in San Francisco on Aug. 27. He's been limited in practice since, and said Wednesday he may not know until just before kickoff if he'll be ready to go.
"You can't really expect anything with hamstrings," Foster said. "Just taking it day by day. It's frustrating, but injuries are part of the game. You can't escape them, if you play this game for a long time. You just have to maintain them, and take care of them when they happen."
Houston coach Gary Kubiak said Foster will be evaluated again Thursday. Backups Derrick Ward, Ben Tate and Steve Slaton shared the snaps in practice in Wednesday, while Foster worked individually on a separate field.
"If Arian's full speed, he can play," Kubiak said. "We want him to play. We need to be at our best to win a football game, but at the same time, we've got to listen to what's going on. As I said all along, the progress has been very good and I know there was more progress (Wednesday), so maybe this conversation is different tomorrow. I don't know. We'll see."
Foster said he ran nearly full speed and was able to make cuts in his individual workout.
"I was running and cutting and frolicking," Foster said.
Kubiak said he'll talk to head athletic trainer Geoff Kaplan before deciding on Sunday. Foster will have input, too.
"You kind of know your body," Foster said. "When it comes to hamstrings, you have to listen to your body. It talks to you. I ran on it and it felt good. You don't want to push it too fast, too soon."
Foster feels no urgency to hurry back, just so he can play in the first game. A year ago, he rushed for a single-game franchise-record 231 yards and three touchdowns against the Colts in the opener. He reached 100 yards rushing in seven more games in 2010, and finished with 1,616 yards to earn an invitation to the Pro Bowl.
"This is a 16-game season, and you don't want to rush back for Game 1 if you're not ready," he said. "I plan on being ready. But if it's not ready, it's not ready."
Kubiak feels good about his options at running back, even if Foster can't play.
Ward, who averaged 6.3 yards on 50 carries last season, is the No. 2 back on the Texans' depth chart. Tate, a second-round draft pick in 2010, broke his ankle in the first preseason game last year and missed the season. He also had a hamstring injury early in training camp, but ran well in two preseason games.
Kubiak says he won't even hesitate to use Slaton, a former third-round pick, who sat out all four preseason games with a hamstring injury.
"I think he kind of got lost a little bit because he missed that time," Kubiak said, "but up until the time he pulled a hamstring, he was excellent through camp. I thought it was really pushing Derrick and Ben, very much so. It was unfortunate, but I think Steve's come back the right way and Steve's ready to be successful again in this league. You never know when your opportunity's going to come, so I've been impressed with what he's done. I'm glad he's on this football team."
The Texans' uncertainty is just another thing for Indy to worry about, after announcing Wednesday that Peyton Manning will miss the opener because of a longer-than-expected recovery from neck surgery.
The Colts ranked 25th in run defense (127 yards per game) last season, and bolstered the unit by adding four former first-round draft picks -- defensive linemen Jamaal Anderson, Tyler Brayton and Tommie Harris and linebacker Ernie Sims. Harris was waived Saturday, but Colts coach Jim Caldwell liked what he saw from the defense in the preseason.
"But the real test is obviously when we start playing in the regular season," he said. "It will be a great opportunity for us to see the adjustments that we've made, how much they'll be able to improve us and things of that nature, but we're excited about that opportunity."