Center Koppen heads to market

While there were talks between center Dan Koppen and the Patriots earlier in the offseason about a possible contract extension, the expected has unfolded: Koppen is headed to the open market, according to a source.

The Patriots' starting center since 2003, Koppen could still return to the team if things don't work out in free agency.

But for now, the former Boston College snapper who joined New England as a fifth-round draft choice in '03 and has started 120 of 121 games played, will explore other options.

One question teams figure to have is Koppen's health after he injured his ankle in the season opener. He didn't play after the injury in 2011, although it's possible he could have returned later in the year if the team could have afforded to hold a roster spot. Koppen is now fully healthy.

Earlier this year, quarterback Tom Brady explained the comfort level he has with Koppen by saying, "There's only one other butt on this planet I like: Koppen's and my wife's."