Cameron, who turns 37 on Friday and is a three-time Rawlings Gold Glove Award winner, has started only one game in left field in his entire career, and that was back in 2000. In fact, he hasn't been in either corner outfield spot since a severe collision with Carlos Beltran in 2005.
Meanwhile, the 26-year-old Ellsbury -- voted by fans at MLB.com as the Defensive Player of the Year in 2009 -- started 17 games in left for the '07 Red Sox and 50 in '08, because Coco Crisp was still with Boston that that time.
In a phone conversation with MLB.com on Tuesday, Red Sox manager Terry Francona said that he and bench coach/outfield instructor DeMarlo Hale held a conference call with Ellsbury shortly before Christmas to inform him of the decision.
"After we signed Cam, I kind of knew how I felt about it," Francona said. "But I wanted to take the time to talk to [general manager] Theo [Epstein] and DeMarlo and just kind of get their thoughts. I think I we were all in agreement that having Jacoby in left and Mike in center made the most sense. Then it was just a matter of talking to Jacoby. I was down in Florida right before Christmas with DeMarlo going over some Spring Training stuff so we called him together."
What were the determining factors?
"Mike's played center field the majority of his career and he was great about it," Francona said. "He said, 'I'll play anywhere.' He's got those long strides that I think are built for center field. I think Jacoby's first-step quickness just really ... I think he'll be dynamic over there. We've seen Carl Crawford [with the Rays] for so many years. You've got a center fielder playing left field. That thought has intrigued us for a long time."
Much like Crawford, Ellsbury is an elite basestealer. In fact, he led the Majors with 70 steals in 2009. But Francona didn't view wear and tear Ellsbury experiences from stealing as a reason to move him from center to left.
"I've heard that," Francona said. "I can't say I know that because I wasn't a base stealer. If that helps, good. That wasn't necessarily the case. I've seen that written a few times. We're just trying to put our best team out there."
Though Ellsbury played only in center field in 2009, Francona remembers how adept he was in left the previous two years.
"He did a great job," Francona said. "I think he was probably a little disappointed when I called him, which I understand. But I think, as far as our team goes, this has a chance to really make us better, and that's what we're trying to do."
The manager wanted to make sure Ellsbury didn't view the move as a demotion.
"That's exactly what I think his concern was," Francona said. "And you know what -- I understand that. But it's not [a demotion]. If Jacoby would have played center field for us next year, I would have been just fine with that. Again, depending on who we have on our team, it's my job to put guys where I think we'll be the strongest. And I think this is going to make us better defensively."