Patriots outside linebacker Adalius Thomas has his sights set on grounding Peyton Manning and the Colts on Sunday night.

The Providence Journal / Bob Breidenbach

FOXBORO — Adalius Thomas isn’t letting on when asked if he’ll be the one covering Colts tight end Dallas Clark on Sunday night.

The Patriots don’t want to tip their hand, he said.

But with Rodney Harrison, who has covered him effectively in the past, unable to be on the field, Thomas is the top candidate to shadow Clark.

He’s not a bad option.

One of the reasons New England wanted to sign Thomas last year when he was a free agent was because of his versatility: at 6-foot-2, 270 pounds, he has a combination of speed and size that allowed him to play nearly every position on defense at one time or another for his previous club, the Ravens.

Thomas has experience against Clark, who is listed at 6-3, 252. In the 2006 divisonal playoff round, Thomas covered Clark and held him to two catches for 41 yards. In Indianapolis’ three other playoff games that season, the tight end averaged 6.3 catches for 92 yards.

Previous success or not, Thomas isn’t saying if he’s drawn Clark this week.

“I think it depends on the situation,” Thomas said. “It depends on the way the game goes. I don’t think that you can just (ask) one guy to cover Dallas Clark because he’s such a good player.”

After catching 58 passes for 616 yards and 11 touchdowns last season, Clark got off to a slow start this year and missed the Colts’ second game with a knee injury. He’s pulled in 15 of his 27 receptions over the last two weeks, including a seven-grab, 94-yard, two-touchdown effort in Monday night’s loss to Tennessee.

Thomas may also be hesitant to talk about potentially facing off against Clark because when last the Pats and Colts met, he didn’t see the field much. New England began the game in a nickel-type defense, with four linemen, five defensive backs and two linebackers, and Thomas didn’t play the first two defensive series.

Iowa native Clark, who played his college ball in his home state, is known for his route-running, which Thomas cited as one of the reasons it’s difficult to cover him. Upping the difficulty are the gyrations and changes Indy quarterback Peyton Manning often makes at the line of scrimmage: moving his running backs, altering his protection and trying to stump defenders by varying his snap count.

Just as Clark is coming off a big game, so is Thomas, as he had eight tackles (four solo), two sacks and two other quarterback hits against the Rams on Sunday.

Part of his increase in production after recording six sacks last year, Thomas already has five this season is a move to outside linebacker after beginning his Patriots’ career at inside backer.

But part of it is familiarity.

“A lot,” Thomas says when asked if he’s more comfortable this year. “There’s a lot more comfort because you’ve been in the same scheme so it’s a lot easier now to digest the calls and understand what you have to do.”

Earlier this year, Bill Belichick praised Thomas’ work ethic and adaptation to the Patriots’ schemes.

“Adalius is a smart guy who works hard,” Belichick said. “I think he has really become one of the leaders on defense. Going into his second year he knows more of what he is doing, as opposed to feeling like ’I have to learn this and learn that.’ He has been very positive in his work ethic and with helping some of the younger linebackers. He really stepped up and gave a lot of leadership and good work ethic to the entire unit.”

Though coming into a new scheme and learning a different position weren’t easy when he arrived in New England, the experience of playing inside has helped because Thomas can understand what he’s seeing from all angles.

smanza@projo.com