When the Patriots officially begin their title defense in early September they'll be without Rob Ninkovich. The veteran defensive end announced his retirement Sunday.

"There's something to be said about going out on top," Ninkovich said during a press conference that includes coach Bill Belichick and many of Ninkovich's teammates. "At the end of the day, I know that I won and that was just doing it as hard as I could, my way."

Ninkovich, 33, was originally a 2006 fifth-round pick of the Saints. He signed with the Patriots in 2009, had four sacks in 2010, and by 2011 he had earned the starting job. From 2011-2016 he started 91 of a possible 96 games and registered 41 sacks. He also appeared in 17 postseason games, was the Patriots team captain in 2013 and 2015 and earned two Super Bowl rings.

"Personally, I can't thank you enough for your contributions to the team, to the organization," Belichick said, addressing Ninkovich. "I never coached a more unselfish player. It was always about the team, about how Rob helped the team. 'What do you need me to do, coach?. ... Whatever you need me to do.'"

Ninkovich's response: "Coach, I gave you everything I had. I hope it was enough. I love this game. Thank you."

Ninkovich retires from a Patriots squad that has the potential to be better than the group that won the Super Bowl in February. New England spent the offseason restocking a roster that was already among the best in the league. The Patriots signed cornerback Stephon Gilmore and veteran linebacker David Harris, and traded for pass rusher Kony Ealy, who may have been acquired as insurance against Ninkovich calling it a career; Ealy now projects as the starter.

Ninkovich had been absent during Patriots' training camp for what Belichick called personal reasons.