Eight years later, Belichick proved that his praise was more genuine than initially thought, as the Patriots agreed with the 32-year-old Kelly on a two-year contract, according to a league source.
"Tommy Kelly is one of the best defensive linemen in the league. He's an outstanding player," Belichick said before the 2005 Patriots-Raiders season opener.
"Kelly plays everywhere. He's a little bit like Howie Long in that Howie Long was a guy that they would move along on the front. They would take Howie and mismatch him against whoever they thought the other team's worst lineman was. There is a little bit of that with Tommy Kelly too, find a guy that they want to go after and stick him there because he does have the flexibility to play outside and inside. He can pretty much play across the board. He can do everything. Play the run, rush the passer, he's good in pursuit. He's a very physical player. He's pretty good."
Kelly might not be the same player he once was in 2005 -- the Raiders released him March 27 in part because of salary-cap considerations -- but Belichick obviously thinks he still has something to offer.
The Patriots have been searching for more help alongside All-Pro Vince Wilfork, the 10-year veteran who has played more than 80 percent of the defensive snaps in each of the last two seasons. The 6-foot-6, 325-pound Kelly adds another option alongside four-year veterans Kyle Love and Brandon Deaderick, who split starting duties alongside Wilfork in 2012. Both Love and Deaderick also enter the final year of their contracts.
Kelly has played his entire career with the Raiders (2004-2012), and in 2008 signed a seven-year, $50 million contract. Among other things, he's been known for his durability, starting all 16 regular-season games in each of the last five seasons. He totaled 45 tackles and 1 sack in 2012. In the two seasons prior to that, Kelly combined for 14.5 sacks, and it’s that interior pass rush that likely intrigues the Patriots.
Ian Rapoport of NFL Network first reported the agreement.