An important distinction

Thomas's role, value are now much greater

Unlike last year, Adalius Thomas (right) should be a key figure against the Colts Sunday. Bill Belichick's richest free agent signee has mastered the defense. (Jonathan Wiggs/Globe Staff)

FOXBOROUGH - During the fourth quarter of the Patriots' 23-16 victory over the St. Louis Rams last Sunday, coach Bill Belichick called Adalius Thomas - and only Thomas - over to the sideline during a break in the action to deliver instructions for what he wanted the defense to do.

The tableau of Thomas and Belichick huddling one-on-one on the sideline at a crucial point in the game said more than any statistic or quote could about the outside/inside linebacker's progress in his second year with the Patriots. He's sure of himself and the Patriots are sure of him.

At this time last year when the Patriots were preparing to play the Indianapolis Colts, Thomas turned out to be an extra instead of a leading man in the game plan, essentially replaced at inside linebacker by safety Rodney Harrison and relegated to just three of the 10 series in New England's 24-20 victory. The 6-foot-2-inch, 270-pounder figures to play a much more prominent role Sunday, when the Patriots clash with the Colts. Thomas not only might inherit some of Harrison's duties covering tight end Dallas Clark, but some of his leadership responsibility as well.

The 31-year-old Thomas, who leads the team in sacks with five and is fifth in tackles (credited by coaches with 31), has become the versatile and valuable player the Patriots envisioned when they signed him to a five-year, $35.04 million deal, the largest free agent payout of the Belichick era.

Thomas has been on the field for 99 percent of the Patriots' defensive snaps this season. He's started all seven games at outside linebacker, but shifts inside in some of the sub packages that feature five and six defensive backs and is occasionally used as a down lineman to rush the passer in sub defenses.

When Thomas was signed away from Baltimore, many thought it was for the purpose of helping the Patriots slow down the Colts, who had taken advantage of the New England linebacking corps in the 2006 AFC title game. That's why his limited role against Indy last year was all the more surprising.

"That just goes to show you that everything that you hear you can't believe," said Thomas. "I know I never said that. I know I never heard them say, 'Well, we brought him in for this.' It's never been that point. I think that's something that the media kind of jumped on, and it could be a fair assessment based on how we played in Baltimore and different stuff like that. But that was never the case, and it's never been brought up that way. That was something that the media kind of assumed and ran with. Then it didn't come to light."

Some thought the Patriots misused Thomas last year when he started the season as an inside linebacker in the team's 3-4 scheme, but that was all part of Belichick's plan to familiarize him with the defense and make the most of his talent. It just took a little longer than expected.

Thomas said he's reacting instead of thinking this season. Things as basic as making calls when he's in charge of the huddle are much easier than last season.

"It's easier to call them because I don't even have to figure out the whole call in order to call them," said Thomas. "You know what calls go with what coverage and different stuff like that."

Being in command of the huddle automatically puts Thomas in something of a leadership role, a job he shares with fellow linebackers Mike Vrabel, Tedy Bruschi, and rookie Jerod Mayo. And with Harrison out for the season, Thomas's role as a leader could expand.

"I think AD has always been a vocal guy. He was a vocal guy last year," said cornerback Ellis Hobbs. "Whether they were listening to him or not is a different story, but I think he's always been a vocal guy. He's always stood up for us; that's first and foremost.

"He stands up for the players in any situation - with the [Players Association], the organization, the team, this and that. He holds no punches. He doesn't just go out there and say stupid stuff, but at the same time, he says what's on his mind if it needs to be said."

Thomas acknowledged that in his younger days, being reduced to a spare part in the Patriots' defensive game plan against the Colts would have bothered him. Now he sees the bigger picture, which with the Patriots means any player from Bruschi to Kevin Faulk can be asked to accept a lesser role in any given week.

"As long as we win, I really don't care," said Thomas. "I'd rather have a win and no tackles and no plays than five sacks and a loss. That's basically what it is. When I was younger, it really mattered. You wanted to get in. It didn't matter whether you played a good game or whatever. Now you just want to go out there and contribute however you can contribute. Like I've said before, the faster you accept your role, the better you'll do at it, so whatever your role is, you just accept it and move on."

Whatever Thomas's role is this time against the Colts, it has to be bigger than last year's, right?

"You'll have to find out on Sunday around 8, 8:15," said Thomas with a smile. "That's the only thing I can tell you. It just really depends. Whatever is best for the defense I'm willing to accept, if I play five snaps or if I play all of the snaps. It will be interesting to see how Bill sees it's going to unfold."