"He's played left field here before. He's fairly familiar with it," Hillman said. "It'll be less taxing on his lower half, and hopefully, it'll be better for his legs staying fresh and healthy as we get into the break."
Guillen, usually the right fielder, was the designated hitter on Wednesday night at Detroit because his legs were hurting, but he was back in the outfield in Boston.
David DeJesus was shifted to his old post, center field, and newcomer Ryan Freel was in right field in the series opener against the Red Sox, who took an early 3-0 lead off starter Luke Hochevar.
"David has played center here before and he may need a little help, depending on how well we pitch, with balls in right-center," Hillman said. "Ryan's played more center but plenty of right. I'm just trying to do the smartest thing, not only for our bodies but with coverage in the outfield."
Fenway poses a challenge for outfielders because of the towering Green Monster in left, the odd angles and deep niche in center, and right field, which curves in to the Pesky Pole just 302 feet down the line.
"It's tricky no matter where you put 'em and no matter who you've got out there," Hillman said.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.