Dan Koppen tough for Pats to replace

FOXBOROUGH, Mass. -- Asked to describe his relationship with quarterback Jim Kelly, former Buffalo Bills center Kent Hull once noted, "We were almost intimate."

Tom Brady struck a similar tone last year when talking about Dan Koppen, his center with the New England Patriots. "There's only one other butt on this planet I like: Koppen's and my wife's," he said on Boston sports radio station WEEI.

There's no way around it: There's a certain bond that's formed when a quarterback spends more than 1,000 snaps each season with his hands hovering near an offensive lineman's hindquarters.

Ever since the Patriots drafted center Koppen in the fifth round (164th overall) of the 2003 NFL draft, it's been Koppen's derriere that's been closest to Brady as he's become arguably the league's top quarterback. Koppen has made 120 career appearances, missing only eight games in his nine-year tenure with New England.

But Koppen is being forced to the shelf after suffering a fracture in his left ankle in Monday's 38-24 triumph over the Miami Dolphins. The injury came as Koppen tried to pave a path for Brady on a seemingly harmless quarterback sneak late in the first half.

The Patriots' offensive line, already dinged up with right tackle Sebastian Vollmer nursing a back injury, has lost its own quarterback. Koppen is in charge of the pre-snap reads and adjusting protection on the line.

"He's the best, and there's no one like him," Brady said of Koppen after Monday's game. The two shared a moment on the sideline when Koppen hobbled out on crutches to watch the final moments. "I think he and I have a great chemistry between the two of us. We always have, and he's one of my great friends. Hopefully he's back at some point."

Just when that point will be isn't clear. Koppen's injury came on his 32nd birthday. He was to undergo an MRI on Tuesday that was expected to reveal the severity of the injury and help set a timeline for how long he'll be out of action. But it's a safe bet he won't be back until the midpoint of the season at the earliest.

Suddenly everything from the center to the right tackle is a bit unfamiliar to Brady. With Vollmer out, rookie Nate Solder made his pro debut Monday. Next to Solder at right guard was 11-year veteran Brian Waters, who was signed by the Patriots last week to provide depth on the interior line. Instead he's been thrust into a bigger role than even he probably expected at the onset.

The Patriots might need a little more depth, but that doesn't mean they can't fill Koppen's shoes in-house, as daunting as that might seem.

Over the past five seasons, Koppen has delivered roughly 95 percent of Brady's total snaps, including 97.6 percent of those snaps (1,104 overall) during the 2010 campaign.

According to analytics site Pro Football Focus, Koppen graded out as the 10th-best center in the league (among those who made at least 75 percent of their team's snaps last year). He allowed a modest 16 quarterback pressures, two hits and three sacks.

But stats can't quantify everything, and after Koppen's injury Monday night, former teammate Tedy Bruschi wrote, "By the nature of the position, there is a connection there; sometimes you just don't want to get used to another lineman's butt."

Brady has no other choice.

Dan Connolly appears set to step back into a starting role. Filling in for an injured Stephen Neal last season and subbing for Logan Mankins at left guard during his contract dispute, Connolly was ranked by PFF as the 26th-best guard among those who played at least 50 percent of their team's snaps. He allowed 17 pressures, six hits and just one sack.

An ankle injury slowed Connolly during the exhibition season, and the addition of Waters bumped him from the starting lineup. But offensive coordinator Bill O'Brien was impressed by Connolly's ability to step right in at center Monday night.

"[Koppen is] a guy that's played a lot of football for us at a very important position," O'Brien said Tuesday. "That's not something that's an easy thing to adjust to, but I do think that Dan Connolly went in there last night and performed pretty darn well for the situation he was put into. I'm confident in what he's been able to do for us.

"With [Connolly], we didn't adjust the game plan at all; we did the same things we did during the whole game. Like I said before, I thought he came in and did a good job … the whole line played a very solid football game for us, and he was part of it."

Indeed, Connolly was on the field for four of New England's five touchdowns Monday night and can lay claim to being a key part of an offensive line that allowed Brady to reach the 500-yard mark.

Patriots coach Bill Belichick and personnel director Nick Caserio said during their conference calls Tuesday that they would continue to monitor who is available on the open market and make any roster move they felt would strengthen the team.

One piece of strengthening the team will need in the meantime is the bond between Brady and Connolly.

Chris Forsberg covers the Patriots for ESPNBoston.com.