However, the good news is that Drew and the Red Sox still don't think the ailment will put him on the disabled list. The latest target date for a return is Thursday night for the finale of this three-game series.
Drew suffered the injury on Friday against the Dodgers, so Tuesday marked the third straight game he was not in the lineup.
While doing some running at Fenway during Monday's off-day, Drew felt some discomfort and shut it down. He felt better by Tuesday.
"Came in today, hit some in the cage," said Drew. "I'll go out and hit on the field. I ran back and hit in the cage a few times. It doesn't feel as bad, so I'm real optimistic that we're getting close. I'm going to try and play it safe. If we can buy just a little bit of time and let this thing disappear, hopefully I'll be ready to roll again.
"I'm sore from all the massage, the stretch -- all that kind of stuff -- along with the injury. That being said, just trying to let it catch up. It's headed in the right direction, so I'm very optimistic."
This was the third time the Red Sox have recalled Reddick this season from Triple-A Pawtucket. He was last sent down on June 12, when the club wanted him to get more regular at-bats and summoned Daniel Nava to take his place.
Reddick and Nava started in the same outfield on Tuesday.
To make room for Reddick on the roster, the Red Sox optioned righty reliever Robert Manuel to Triple-A Pawtucket. Boston summoned Manuel from the Minors on Saturday, but he didn't pitch in the two games he was active.
The Red Sox will again have to make a roster move on Thursday, when Daisuke Matsuzaka is activated. Reddick could be sent back down then, depending on Drew's status.
"Big outfield [at Coors Field]," said Red Sox manager Terry Francona. "We don't know how long he'll be here. We'll see what happens. We obviously have some moving parts that we'll probably continue to keep moving because of Dice-K."