The Celtics have signed Marcus Smart, tweets Mark Deeks of ShamSports. There’s been no public announcement from the team, but Smart has been playing in summer league for the club. As the No. 6 pick from this year’s draft, he’ll likely receive a salary worth slightly more than $3.283MM this year, as our chart of salaries for first-round picks shows. The 6’3″ Smart finally joins the NBA after a surprising decision to sit out the 2013 draft and return for his sophomore season at Oklahoma State. An incident in which he shoved a fan during a game caused a stir, but it didn’t seem to have much of an effect on his draft stock, as he was only the second point guard to come off the board. The Celtics already have Rajon Rondo and Avery Bradley in the backcourt, but president of basketball operations Danny Ainge has expressed confidence that Smart can co-exist on the floor with both of them.