BY Craig Larson
Boston Globe Staff Writer

As a point of emphasis, Robert Talley was describing a play last month from the third quarter of a Northeast-10 game at Assumption, to detail the essence, and presence, of Brian Harrington.

And the powerful impact that the hard-hitting junior linebacker is having on his young, but rapidly improving defensive unit at Stonehill College, one that has thrust Talley's club (3-1, 3-0 NE-10) into contention of the conference race entering Saturday's matchup against visiting American International (2-2, 2-1).

"What separates him? . . . It was [third and 10], they had a screen pass out to [Matt Pedone], a real good player. [Pedone] makes someone miss, and all of sudden Harrington comes out of nowhere, and he hits him, and stops his momentum. I thought [Pedone] was going to fall forward for a first down."

He was a yard short.

"That play really defines him," said Talley of Harrington, who, as a first-year starter at middle linebacker, is leading Division 2 in tackles per game (14.0).

"Am I surprised?" asked the 6-foot-1-inch, 216-pound Harrington, who has been tabbed the NE-10's Defensive Player of the Week three times in the first four weeks of the season. "Yes and no, but just trying to perform to the best of my ability."

Initially, his coach had no idea what kind of player Harrington could become, before he arrived from Rockland High. Then, Talley witnessed the relentless work ethic, the passion, the intensity, and the nonstop motor.

"You look at him [in high school], he's playing out of position, at defensive end/outside linebacker, he's a bit undersized," said Talley. "But there were a number of alums calling on his behalf, saying, 'You can't miss on this kid.' "

His first two seasons, Harrington kept plugging away in his transition to middle linebacker. His real impact came on special teams, where he was tabbed MVP of the Skyhawks' unit last year.

"Once he got on campus, you saw a kid that was going to work hard at everything he does," added Talley.

He was just following in the footsteps of his brother, Wayne, 10 years his senior, a former all-NESCAC linebacker at Colby.

"He is the first person I talk to after every game," said Harrington.

But in August, at the start of preseason drills, he was still penciled in as a backup, slotted behind his roommate, junior Mike Hogan.

But then Hogan was ruled out for the season with a heart condition. And sophomore Peter Catal, the starter at strongside linebacker, was dealing with a medical issue that forced him out of the lineup, too.

Suddenly, Harrington had his opening.

In his first start, he racked up 16 tackles at Bloomsburg. Then 10 stops and a sack against Saint Anselm. And 17 more in the thrilling 31-28 overtime victory at Assumption. And last week, 13 in a 30-3 beatdown of archrival Bentley, the anchor for a group that registered six sacks and forced four turnovers.

"The way our defensive scheme is set up, our middle linebacker should have opportunities to make plays," said Talley. "The thing that separates him from other people is that he just works. He has that edge, he doesn't back from contact. And he has that motor."

Harrington said that as much as the injuries "stink," it gives other players opportunities.

"We've had our share of adversity," said Talley. "You look at the defensive front, we have four freshman playing. In the future that will be nice, but right now . . . Young kids are going to make mistakes."

And that is why having a glue guy like Harrington is so essential.

"Every time I talk about him, it's because he works hard, and every other player knows, if I want to be like him, earning those honors, if I want to have the success he's having, I need to work hard too," said Talley. "It raises everybody's level, too."

He is not alone.

Senior quarterback Logan Meyer (14 TD passes) is at the controls of a quick-strike attack (34 points per game) that features deep threat Nate Robitaille (35 catches) and running back Jamal Johnson (5.3 yards per carry).

"We want to stretch the ball out to our athletes," said Meyer, whom Talley lauds for his maturity at the position, and making smarter decisions.

But knocking off AIC for the first time in 16 tries will require making stops. And that starts with Harrington. "We know how good they are, it will be a good test for us," he said. "The Assumption game was the first real test of character for the team as a whole."

And that was a smashing success.

Craig Larson can be reached at clarson@globe.com. Follow him on Twitter @GlobeLars.