"It's just disheartening because you know I put in so much effort this offseason," Foster said on the HBO documentary "Hard Knocks", making his first public comments since the start of training camp. "I was actually in the best shape of my life. I'll still be able to salvage a season out of it. It's not going to be I'm going to be back for two games. S--- happens. You've just gotta roll with it."
Foster had surgery on Aug. 7 to repair the injury that involved a muscle tearing from the bone.
Texans coach Bill O'Brien said Monday he believes Foster will return "sooner rather than later" relative to the original prognosis of his rehab.
"I believe that he's really working hard to get back," O'Brien said. "He's a very hard-working guy right now in that training room."
Foster rushed for 1,246 yards and eight touchdowns last season, catching 38 passes for 327 yards and five touchdowns.
He played in 13 games, missing three altogether and parts of three others because of injuries. In 2013 Foster missed eight games with a back injury that required surgery.