By Shalise Manza Young, Globe Staff

The Patriots are in serious negotiations regarding the contract of tight end Rob Gronkowski, a league source confirms, but nothing is finalized. It is unclear at this time whether the two sides are discussing just a restructuring of the current contract or an extension as well.

Jason LaCanfora of CBSSports.com reported the deal will give Gronkowski a raise and an extension.

A second-round draft pick in 2010, Gronkowski has two years remaining on his four-year rookie deal, which pays him base salaries of $540,000 in 2012 and $575,000 in '13, plus minimal workout bonuses.

He has certainly outplayed those figures - last year, the gregarious Buffalo-area native set new NFL records for his position with 1,327 yards and 18 total touchdowns (17 receiving, one rushing) on 90 receptions.

He suffered a severely sprained ankle in the AFC Championship game against Baltimore, but still played in the Super Bowl, though he was clearly limited. He underwent surgery to repair torn ligaments in the ankle shortly after the season ended and continues to rehab from the procedure.

New England has plenty of salary cap space after the retirement of Matt Light and Tom Brady agreeing to a restructured contract that gave him more up-front money. Gronkowski is one of several young players, including Aaron Hernandez, Patrick Chung and Sebastian Vollmer, whose rookie deal is nearing its completion. Gronkowski, however, is undoubtedly the best of the bunch, and to many has already established himself as the best tight end in the NFL.

Last December, the Pats gave linebacker Jerod Mayo a contract extension, 18 months before his deal was set to expire.

The website ProFootballTalk reported late last night that the two sides had reached an agreement on a re-negotiation of the final two years of Gronkowski's rookie deal.