Carl Nicks is a free agent lineman who has spent the last four seasons with New Orleans. (AP)

We continue our on 15 possible fits for the Patriots in free agency this offseason. With the understanding that the NFL’s franchise tag window is from February 20 to March 5 (which means some of these players we list could ultimately be retained by their team) here are some players worth keeping an eye on that might be a fit in New England when free agency begins March 13:

Carl Nicks
Position: Offensive guard
Age: 26
Height: 6-foot-5
Weight: 343 pounds

Two points: One, we’ve been down this road with Nicks before. And two, this whole entry should be led with the following disclaimer: If Brian Waters decides to retire, then Nicks would be the next best option for the Patriots. Waters said after the Super Bowl that he’d taken two to three weeks to decide on his future, and if he does choose to return, then the whole idea of Nicks to New England is moot. But if Waters does choose to hang ‘em up, the Patriots should focus their attention on landing Nicks, a Nebraska product who was a fifth-round pick of the Saints in 2008.

This wouldn’t be the sort of marquee, skill position signing along the lines of a Vincent Jackson (or even Reggie Wayne) that would get people talking, but the addition of Nicks — who is expected to leave the Saints — would certainly give a big boost to New England’s offensive line. A two-time All-Pro, he’s finished first (2009), first (2010) and second (2011) in Pro Football Focus rankings the past three years, and PFF has him as the fourth-best free agent on the market.

There are some hard decisions to make regarding the interior of the New England offensive line this offseason, as center Dan Koppen and center/guard Dan Connolly are both free agents. The Patriots have Ryan Wendell as a quality backup at both positions, as well as center Nick McDonald, but if Waters does decide to retire (or they don’t re-sign Koppen and/or Connolly) and they don’t believe Wendell is a long-term answer as a starting guard, they would be wise to at least kick the tires on Nicks.

Why it might not work: We already covered the Waters angle. In addition, Nicks could balk at the idea of moving from left to right guard. I’ll also be curious to see how the market for free-agent guards shakes out — Nicks is presumed to be the best of the bunch, but it’s a group that also includes Baltimore’s Ben Grubbs and Philadelphia’s Evan Mathis. And historically, other than Waters, the Patriots have been reticent to bring in veteran offensive linemen, choosing instead to cultivate their own younger talent under the guidance of veteran offensive line coach Dante Scarnecchia.