DAVIE, Fla. -- Arian Foster won't admit it publicly. But he must be quietly proud deep down for all he has accomplished the past several months.

Foster was cut by the Houston Texans after suffering a season-ending Achilles injury last year. There were doubts about how Foster would bounce back, and once free agency opened, Foster went unsigned until a week before training camp when the Miami Dolphins offered a one-year contract.

Two months later, Foster proved to be a quick study and beat out incumbent Jay Ajayi to be the Week 1 starter for Miami. Foster, who was rehabbing without a team in June, will lead the Dolphins' rushing attack against the Seattle Seahawks on Sunday.

"Any time you get the luxury of coming out here and doing what you love for a living, it's always awesome," Foster said of making his regular-season debut. "So I guess in that sense it's special. But I'm just another chess piece out there."

Foster also downplayed his long road back Tuesday: "I wasn't dead. I had an injury. I've bounced back before."

The former Pro Bowler says he has big goals for this season but did not want to share them with the media. Foster has shown flashes of his old self in training camp and during limited reps in the preseason.

There certainly will be doubters. Foster just turned 30 last month, which is the age when NFL running backs usually hit a wall.

Foster, who has a career 4.5 yards-per-carry average, says he is confident in where he stands physically, and that he's ready for the grind of a 16-game season.

"You hear all the geniuses say that is what's supposed to happen at 30," Foster said. "I feel like if you take care of your body and you train like I train, you should be able to do good things."

Foster changed his number from No. 34 to No. 29 this week, because the former number "just didn't look good on me in my opinion." More important, Foster won the trust of his teammates and coaches with solid play in practices and limited reps in the preseason.

"He had a really good camp," Dolphins coach Adam Gase said. "He did everything we asked him to do as far as what we wanted to see in the preseason, and he's been very consistent in his knowledge of the offense in the short period of time that he was here -- it was impressive to watch him [and] how quickly he picked it up."

The Dolphins will need a vintage performance from Foster for a chance to pull the upset. The Seahawks are double-digit favorites against Miami, and last season had the NFL's No. 1-ranked run defense at 81.5 rushing yards per game.

"They've been dominant in this league for years now," Foster said. "They've set the mark of what a defensive team is supposed to do. It's going to be a tough one. But it's a great team to open up with, because you know where you're at after you play them."