Sudden impact: David Baas

(Identifying some free agents who could be a solid fit for the Patriots when the 2011 league year begins.)

Player: David Baas (guard/center, 49ers)

Why sign him? After sparring with Patriots management last summer, starting left guard Logan Mankins appears likely to return in 2011, playing under the franchise tag. However, his future in New England beyond this season remains in doubt. Starting right guard Stephen Neal retired in March, and veteran center Dan Koppen enters the final year of the contract, leaving the Patriots with little long-term stability for their interior offensive line. Dan Connolly looks primed to step into one starting role, but next-best options Ryan Wendell and Rich Ohrnberger are unproven, while rookie Marcus Cannon’s health situation remains a question mark. Baas, a six-year veteran, started every game the last two seasons and has versatility to play both guard and center.

Is there anybody else? The market at interior offensive line features of mix of younger talent – notably Tampa Bay’s Davin Joseph and Oakland’s Robert Gallery – as well as experienced veterans such as Chicago’s Olin Kreutz, Kansas City’s Casey Wiegmann, and Dallas’ Kyle Kosier. The Patriots are particular in keeping with their offensive lineman mold, and prefer to develop players from within their own system, making it unlikely they turn to the free agent market for anyone but a stop-gap solution.

Key stats:

• Pro Bowl guard Logan Mankins missed the first seven games of last season during a contract dispute.

• In 2010, the Patriots were ranked 17th in the NFL rushing up the middle, averaging 3.9 yards per rush (4.3 yards per rush in 2009, ranked eighth in NFL).

• The Patriots had 119 first downs rushing up the middle last season, third-most in NFL (Jaguars-148 and Chiefs-129).

• In 185 first-down dropbacks, Tom Brady was sacked 11 times last year (sacked twice in 243 first-down dropbacks in 2009).

ESPN Stats & Information contributed to this report.