West played three seasons with the Celtics, averaging 12.2 points in 2006-07, his final season with the team. He was then traded to Seattle in a draft-day deal that yielded Ray Allen  and Glen Davis . West was subsequently moved to Cleveland in a mid-season deal where he spent the next two and a half seasons.
In 2008-09, West started 64 games with the Cavs, but he was involved in an incident just prior to the start of last season where he was arrested on weapons charges during a traffic stop.  West, who has said that he suffers from bi-polar disorder, pleaded guilty in July to weapons charges and was sentenced to eight-month home detention, probation and psychological counseling. The terms of the sentence allow him to travel for away games.
In August the NBA announced that he will be suspended for the first 10 games of the upcoming season.
On the court, this has a chance to a solid fit for the Celtics. While visions of Portland’s Rudy Fernandez may have danced through fans heads, West offers a versatile guard who can handle the ball and defend multiple positions. West is also a decent shooter, although his 3-point percentage took a tumble to 32 percent last season.
With West’s arrival the Celtics now have 15 players under contract and two more on non-guaranteed deals, meaning that the roster is essentially set barring a trade. The key thing to note is the flexibility players like West, Von Wafer  and Marquis Daniels  offer. This is how it looks:
SG: Ray Allen, Delonte West, Von Wafer
SF: Paul Pierce , Marquis Daniels, Luke Harangody
PF: Kevin Garnett , Glen Davis, Tony Gaffney (non-guaranteed)