Patriots QB harried by Harrison

Linebacker was force throughout

James Harrison's second strip-sack of Patriots quarterback Matt Cassel (above), on which he went around Matt Light (left), looked a lot like the first. (Jim Davis/Globe Staff)

FOXBOROUGH - James Harrison stood in his corner of the Steelers locker room, his work terrorizing the Patriots done for the evening, and held court for a small cluster of reporters. One of them asked him if he felt unstoppable. Well, he reasoned aloud, anyone can be stopped.

"He can't be stopped!" teammate and fellow linebacker James Farrior hollered from the next locker. "Y'all see it."

And it was clear, even through the constant, steady rain at Gillette Stadium yesterday during their 33-10 loss to the Steelers, that the Patriots had no answer for Harrison or his teammates. Harrison's two strip-sacks of Matt Cassel in the third quarter keyed the Steelers' defensive domination. Cassel committed four consecutive turnovers in the second half, melting under the pressure that the NFL's best defense presented.

The Steelers held the Patriots to 81 total yards in the second half, sacking Cassel four times and intercepting him twice. All of that could be traced to Harrison, who belongs on any short list of the league's most destructive players.

Teammates voted Harrison the Steelers MVP last season, when he collected 8 1/2 sacks and forced seven fumbles while also playing special teams. Harrison already had matched that production before yesterday, entering with 12 sacks and four forced fumbles. Those numbers jumped to 14 and six at the expense of left tackle Matt Light, whom Harrison rendered inanimate with his track-star speed off the edge.

"He basically took over the game," Farrior said. "He imposed his will today. He's been doing it all year. I can't say enough about the guy. I don't think he really gets the attention he really deserves. Some of the star defensive players in the league, I don't think he gets quite as much attention."

Said outside linebacker LaMarr Woodley: "If you don't know anything about James Harrison, and you're around the league, something's wrong. That's just how I feel. This guy plays special teams. This guy plays defense. This guy plays every play out there. How can you not look at a guy like that?"

He made the Patriots take notice. Harrison single-handedly prevented them from getting back in the game. The Patriots began a drive with five minutes left in the third quarter, still trailing by only 10 points, needing a response after the Steelers turned Matthew Slater's fumbled kickoff into a quick touchdown.

For most of the first half, while the Patriots lined up "empty" - with no running back - Harrison and Woodley drifted into pass coverage. Coach Mike Tomlin noticed on film how quickly Cassel fired the ball out of that formation, and he believed his outside linebackers wouldn't be able to reach the quarterback in time.

Harrison also had been testing Light, trying to drive him back with bull rushes and decipher if the Patriots were running or throwing. Once the Steelers surged ahead, though, Harrison knew they would pass.

"We didn't have to sit there and try to guess what they were doing," Harrison said. "It just gives you a lot of freedom."

When the Patriots stopped lining up without empty backfields, Harrison grew excited - he didn't have to worry about anything but pressuring Cassel. He feels, no matter who is blocking, that he can blow past him and into the backfield.

And so, as the Patriots began their drive after Slater's fumble, Harrison bolted up field, hell-bent. Harrison waited for Light to put up his outside arm, so he could slap it away. He had Light set up.

Harrison sped around Light with staggering ease. Cassel had dropped only a few steps, and he moved up in the pocket as he cocked his arm. Harrison was too fast, and he saw the ball hovering next to Cassel's body, ready to be smacked away.

"I try to do that every time I get to the quarterback," Harrison said. "I want it all."

And he got it. Woodley pounced on the ball on the Patriots' 26-yard line, leading to a Steelers field goal. When the Patriots got the ball back, they could run only five plays before Harrison struck again. Using the same approach, and the same exact move, he stripped Cassel again, and this time Farrior fell on the ball.

Cassel entered Gillette Stadium yesterday as perhaps the hottest quarterback in the NFL, having thrown for at least 400 yards against the Jets and Dolphins in consecutive weeks. The Steelers bullied Cassel into completing only 19 of his 39 attempts for 169 yards and a 39.4 quarterback rating. Once the Steelers hit him, players said, Cassel became a different quarterback.

"Definitely," Woodley said. "Once guys started coming in and started hitting him, he wasn't as comfortable sitting in the pocket. Once James got him two times, that really rattled him, forced to him to get the ball out a little bit faster."

Adam Kilgore can be reached at akilgore@globe.com