Is the dynamic Arian Foster era over in Houston?

Foster's injury could spell end of run in Houston (0:32)

ESPN Texans reporter Tania Ganguli explains why we may have seen the last of Arian Foster in a Houston uniform after suffering a torn Achilles against the Dolphins. (0:32)

MIAMI GARDENS, Fla. -- For a long time, Arian Foster just sat there as his teammates got dressed around him.

He looked blankly down at the ground. He took a towel and threw it over his head, then dropped his head into his hands. He scooted back toward his locker and sat there, staring ahead. At some point, he changed, spoke to reporters and then picked up a set of crutches to leave Sun Life Stadium.

The Houston Texans lost the game, 44-26, and they might have lost Foster -- their star running back and the engine of this offense for so many years -- for the season. Maybe for good.

With just under five minutes left in the game, Foster tore an Achilles tendon. The exact severity of the injury is unknown, but with only 10 weeks left in the season, there's a good chance Foster's year is finished.

"That's life, man," Foster said. "It ain't perfect. Just gotta keep fighting."

The Texans have known for the past couple of years they're just going to have to make do with Foster being a part-time player. They knew he wouldn't be available for 16 games and were content with that, given how dynamic he is when he's healthy.

But next season, Foster is due to earn $6.5 million with a salary cap number of $9.3 million. The Texans would save $7 million in salary cap space if they release Foster. They save a little bit on roster bonuses if Foster gets injured, but could decide they won't get enough healthy games out of him to justify that. He'll be 30 next season, an age when anyone's body heals less quickly, especially that of a running back who has been loaded with carries. It's the cruel reality of being an NFL running back.

"I think he's done a lot in the two years I've been here," Texans coach Bill O'Brien said. "He's done a lot for us and I feel bad for him. That's all I can tell you. I hate that part of the game. There's nothing you can do about it, but I feel bad for the guy."

He has done a lot for the past two Texans regimes.

Right now, Foster is one of the most productive offensive players in NFL history. His 115 yards per game from scrimmage rank third in NFL history, behind just Jim Brown and Barry Sanders. Adrian Peterson ranks fourth with 114 yards per game from scrimmage.

Signed as an undrafted rookie in 2009, Foster finally started getting looks and made the most of them toward the end of that season. His first 100-yard game came in Week 17 that year, in a win over the New England Patriots. His coming-out party, though, came after that. In the first week of the Texans' 2010 season, Foster gained 238 yards and scored three touchdowns in a win over the Indianapolis Colts.

Since that season, the Texans have been 3.2 percent worse in the red zone, 4.3 percent worse on third downs, .14 yards per rush worse and .69 yards per pass attempt worse without Foster on the field. Only Marshawn Lynch has had more carries than Foster during that time, despite the fact that Foster has missed 14 full games since 2010.

When he's healthy, he's exceptional. His vision and physical ability are incomparable together. He's so smooth, he makes it look easy.

But Foster has played only one 16-game season in the past five. He's had at least seven injuries since 2011.

More and more often, "when" is now a pronounced "if."