The Red Sox have spent an inordinate amount of the 2012 season practicing their subtraction, but a key addition finally looms.

All-Star center fielder Jacoby Ellsbury, who hasn't played since injuring his shoulder in the home opener, will head to Florida and could began a rehab assignment at designated hitter as early as Friday, manager Bobby Valentine said.

"It's great," Valentine said prior to last night's 5-1 win against Toronto. "I'm optimistic. I'm cautious, but I think it's great that we've gotten him to the point where he's back on the field. That means you start looking forward to the time he's on the field here. But he's not on the field yet."