He was later moved back to the point guard position.
In 2005–06, West averaged 11.8 PPG, 4.1 RPG and 4.6 APG.
On February 12, 2006, he was named to represent the Celtics on the sophomore team for the Rookie Challenge at NBA All-Star Weekend.
On June 28, 2007 (during the 2007 NBA Draft) the Celtics traded West to the Seattle Super Sonics, along with Jeff Green (their 5th overall pick) and Wally Szczerbiak in exchange for Ray Allen and Sonics' 35th overall pick Glen Davis.
On February 21, 2008, West was part of a three-team trade that sent him, Ben Wallace, Joe Smith and Wally Szczerbiak to the Cleveland Cavaliers.
West averaged 18.9 points and 6.7 assists per game, shooting 41% from three-point range, as a junior. Joe's after his junior campaign and was selected by the Boston Celtics as the 24th pick in the 2004 NBA draft.
His efforts helped the Hawks to go 27–0 in the regular season, and earn an Elite Eight appearance in the NCAA Tournament. In his first season, he struggled with injuries, playing a total of just 39 games, mostly coming off the bench.
In addition to his role as the starting shooting guard, he also served as the backup point guard, manning the position when Mo Williams was not in the game.
He emerged as a talented backcourt defensive player, guarding a variety of players ranging from the 6'3" Ben Gordon to the 6'10" Hedo Türkoğlu.
He averaged 4.5 points, 1.7 rebounds and 1.6 assists per game.
After making the transition to point guard in his rookie season, West was named the starting point guard at the beginning of the 2005–06 season by head coach Doc Rivers.
The trade also sent Larry Hughes, Shannon Brown, Drew Gooden, and Cedric Simmons to the Chicago Bulls and Donyell Marshall, Ira Newble, and Adrian Griffin to Seattle.