The idea behind the move is aiming to limit the chances of Crisp getting injured. The 35-year-old dealt with a neck injury for much of the 2014 season, which sidelined him at times.
"We feel like we have a better chance to keep him healthy out there," Melvin said. "He had some questions, but he's going to do the best he can with it. There's definitely a transition period with it, but we'll see how it goes."
Crisp started 15 games in leftfield in 2012 while Yoenis Cespedes was injured and has played 232 games at the position over his 13-year MLB career.
Melvin said that with Crisp in left, Sam Fuld and Craig Gentry will platoon in the centerfield spot. He said Crisp has been handling the change "like a pro," but admitted "there's also a pride factor for a guy who is one of the premier center fielders."
Crisp hit .246 with nine home runs, 47 RBIs and 19 stolen bases in 2014, one year after hitting a career-high 22 home runs and 66 RBIs in 2013.
Oakland signed Crisp as a free agent in December 2009. He signed an extension with the A's before last season that runs through 2016, with a vesting option for 2017. He is due to earn $11 million this season.
- Phil Watson