Thomas scooped up a loose ball in the first quarter and sprinted along the left sideline. He stayed inbounds by the tips of his toes, regaining his balance as he rumbled 59 yards into the end zone. At the time it was called a touchdown.

Then the red flag landed on the field.

As Miami quarterback Chad Henne was throwing the ball, Tully Banta-Cain tackled him from behind, jarring the ball loose. It was ruled a fumble, but after review it was determined Henne’s arm was going forward, resulting in an incomplete pass. No touchdown.

“I was heartbroken,’’ Thomas said. “I was trying to get the [extra point] kicked and everything as fast as possible. You always play until the end of the play because you don’t see what happened. I just know that the ball was on the ground and you pick it up and do what comes natural, whatever that may be. It’s not often that a defensive player gets the ball in their hands, so if you do, you want to take advantage of it. So I was just trying to get some points on the board and help the team win.’’

Recalling the moment brought a smile out of Thomas, who hasn’t had much to smile about in recent weeks. Thomas was a healthy scratch against the Titans Oct. 18 for the first time since his rookie season in 2000. Coach Bill Belichick’s reasoning for the decision was that he went with the players he believed gave the Patriots the best chance to win. When Thomas faced the media the following week, he answered questions about his play, expectations of coaches, and his future. All he could promise at the time was that every time he is called upon “I’ll be ready.’’

Thomas returned to the field against Tampa Bay a week later and yesterday found himself in the midst of key plays against Miami’s unpredictable offense.

In the third quarter, with the Patriots leading, 24-17, the Dolphins had second and 8 from the New England 44. Running back Ronnie Brown took the snap and handed the ball to Ricky Williams. Williams then handed it to Henne, but Thomas was there to wrap Henne up for the sack, forcing a third and 19.

It was the way Williams was carrying the ball that tipped off Thomas.

“It wasn’t like he was trying to run,’’ Thomas said. “Usually, when he gets the ball, he’s at full speed. It was just instinctive. I don’t really know. That’s what I saw.’’

Two plays later, the Dolphins were forced to punt.

Thomas had two tackles for a loss and a batted-down pass.

As a unit, the Patriots defense was challenged by not only facing the Wildcat but the option as well.

“It was just a new wrinkle they added to it,’’ Thomas said. “They always have some type of wrinkle, so we talked on the sideline and adjusted to it. It hurt us a little bit with missed assignments, but other than that I thought we did a pretty good job.’’

With so much to be expected, Thomas said the defense was waiting for anything and everything.

“It was like they had been in the Wildcat and so we knew they had a lot of different things from the pass to trick plays and different stuff like that, so when they kept running it, we knew it was going to be something sooner or later,’’ he said. “We were just reading the keys and trying to be instinctive off of it.’’

Monique Walker can be reached at mwalker@globe.com.