BOSTON — Boston Celtics forward Brian Scalabrine is expected to miss about a month due to the effects of concussions that have bothered him since January.

Team spokesman Jeff Twiss confirmed Tuesday that Scalabrine has been diagnosed with post concussion syndrome.

Coach Doc Rivers said April 1 has been set as a tentative return date for Scalabrine, who underwent further tests after missing Sunday's game against the Detroit Pistons — the 12th in the last 15 games he has sat out.

Scalabrine had concussions in a week in January and sat out nine games. He returned and played three games before an injury against Denver last Monday that was first described as a strained neck but was likely another concussion.