After 15 years in the NBA, Oklahoma City Thunder forward Nick Collison is retiring from the NBA, he told ESPN on Thursday.

Collison, 37, entered the league in the famed 2003 draft class along with LeBron James, Carmelo Anthony, Dwyane Wade and Chris Bosh, selected 12th overall by the Seattle SuperSonics. He appeared in 910 regular-season games, and 91 playoff games, third most in franchise history (behind Gary Payton and Fred Brown).

The 6-foot-10 forward missed his entire rookie season because of a shoulder injury. He spent his entire career with the Thunder organization, moving with the team from Seattle in 2008. He was the last remaining player with the franchise that played games in Seattle. (Russell Westbrook was selected fourth overall by the Sonics in 2008, but never played in Seattle). Westbrook is now the only player left on the Thunder from their 2012 Finals team.

Collison is in a rare class of players to spend his entire career with one franchise despite not ever being an All-Star. The only players to spend their career with one franchise and play more games than Collison: John Stockton, Dirk Nowitzki, Tim Duncan, Reggie Miller, Kobe Bryant, John Havlicek, Tony Parker, Manu Ginobili, Joe Dumars, Hal Greer, Calvin Murphy, Alvan Adams, David Robinson, Isiah Thomas, Kevin McHale, Fred Brown, Bill Russell, Jerry West, James Worthy and Tom Sanders. Only eight players have spent more years with a single franchise than Collison.

Known as one of the top glue guys in the league, Collison's best season came in 2007-08 where he averaged 9.8 points and 9.4 rebounds per game with 23 double-doubles. He ranks fourth in Sonics/Thunder history in total rebounds, sixth in blocks, fifth in field goal percentage and ninth in minutes played.

Collison spent four years at Kansas, appearing in two Final Fours, losing in the national championship game to Anthony and Syracuse in 2003. He left Kansas as one of the most decorated players in its storied history, named national college player of year in 2003, consensus first-team All-America and Big 12 Player of the Year.

Collison finishes his career with averages of 5.9 points, 5.2 rebounds and 69 career double-doubles.