Dolphins running back Daniel Thomas was supposed to be the answer. Instead, he's merely part of the answer. And for now, he'll take that role.

In two-plus NFL seasons Thomas has had to battle concussions, a knee injury, an ankle injury, fumbles, Reggie Bush and Lamar Miller. Yet none of that prevented him from turning in the best game of his career on Sunday. It was an unprobable performance because no one was sure he would play due to his ankle injury.

"We're all grown men," said Thomas, who sparked the offense by rushing for a season-best 105 yards last week's 34-28 victory in frigid Pittsburgh. "You've just got to be ready when your opportunity is called."

That hasn't always been the case for Thomas, the disappointing second-round pick from Kansas State in 2011. So far this season he's teamed with Miller to form the NFL's 23rd-worst rushing attack at 95.8 yards per game.

But Thomas might have to carry more of the load this week. Miller left last week's game with a concussion. He has to pass the NFL-mandated concussion testing before being cleared to play in Sunday's showdown against New England.

That could mean Thomas (93 carries, 384 yards, 4.1 yards per carry, four touchdowns) is the main ball carrier in a game crucial to the Dolphins' playoff hopes.

Coach Joe Philbin said Thomas can do the job by doing two things: "Just taking advantage of his opportunities and being productive."

Thomas did that in Sunday's fourth quarter when he rumbled 55 yards to the Steelers' 16-yard line. Two plays later tight end Charles Clay bulled his way into the end zone, giving the Dolphins a 31-28 lead.

That run was the type of the play the Dolphins thought they'd get from Thomas when they traded into the second round to acquire him

Thomas, the backup to starting running back Reggie Bush, rushed for a career-best 107 yards in his NFL debut against Houston. He followed that with a 95-yard game against Cleveland. The 202 yards rushing are the third-highest total for a Dolphins rookie in his first two games.