It was a mere formality after the Minnesota Timberwolves signed Greg Steimsma to an offer sheet (reportedly one-year, $3 million) Saturday, but the Boston Celtics have officially rescinded their qualifying offer to the restricted free agent so that Stiemsma can sign with the Timberwolves as an unrestricted free agent. Via Gary Washburn of the Boston Globe:

#celtics officially rescind qualifying offer to Greg Stiemsma, allowing him to become unrestricted free agents and sign with #timberwolves

July 24, 2012 12:54 pm via TweetDeckReplyRetweetFavorite

@GwashNBAGlobe

gary washburn

Based on the new salary cap rules, the Celtics could not offer Stiemsma more than the bi-annual exception (starting at roughly $1.95 million). Stiemsma averaged 2.9 points, 3.2 rebounds and 1.9 blocks in 14 minutes per game as a 26-year old rookie in Boston. Prior to Boston, Stiemsma played professionally in Turkey, South Korea, and the D-League.

On Saturday when Stiemsma was set to sign Minnesota’s offer sheet, the Celtics signed center Jason Collins to the veteran’s minimum for one season. Collins will compete with rookies Jared Sullinger and Fab Melo for reserve minutes in the frontcourt.