Lowell suffered the injury making a diving stop in the top of the first inning of Wednesday's game against the Tigers. The loss of Lowell, one of Boston's best hitters and fielders, will be an early-season challenge for the Red Sox.
"What I do know is that he'll be in a splint for approximately a week," said Red Sox manager Terry Francona. "I think the hope is that it's something that when the DL stint is over, he can play. It's all going to be determined by how he responds."
An MRI exam, which Lowell underwent on Thursday afternoon, actually provided good news. Originally, Lowell was worried that he could miss as much as a month of action. Now, there's a chance he'll be ready to return when his DL stint expires.
"I mean, I'm frustrated because I'm not going to be playing for a little while," said Lowell. "I think I was encouraged with the MRI that it wasn't a big tear or anything. Then it would have been significant time. They want me to immobilize it for four or five days before I do anything. I think the smart thing was to go on the disabled list and take it from there. I'm hoping the swelling goes down a lot more in the next couple of days."
The Red Sox purchased the contract of infield prospect Jed Lowrie from Triple-A Pawtucket and activated him in time for Thursday's game. Lowrie spent the first two games of the season on the roster when the Red Sox were in Japan playing the Oakland Athletics.
The Red Sox felt even more urgency to add Lowrie to the roster when utility infielder Alex Cora felt a twinge in his right elbow during pregame drills on Thursday. Cora's specific injury has yet to be announced. Fortunately, Cora made a big improvement throughout the day and he should be available off the bench by Friday.
The switch-hitting Lowrie -- who plays all over the infield -- will mainly be used off the bench during Lowell's absence.
The Red Sox are fortunate in that they can move first baseman Kevin Youkilis -- a third baseman throughout his Minor League career -- across the diamond.
Meanwhile, consummate pro Sean Casey will move into the role of starting first baseman over the next couple of weeks. Both players -- Youkilis on defense and Casey at the bat -- played huge roles in Thursday's 12-6 victory over the Tigers.
"It will be good to get out there," said Casey. "It will also be good to have Mike back. I think that's the catch-22. Any time you have an injury, it's good to have a guy who can step in, and hopefully I'll be able to go in there and do a good job, and that's what I'm planning on doing."
The Red Sox have no doubt about what Casey can do. In essence, this is the type of reason he was signed in the winter.
"I think you could tell Case in December to go hit and he could put a good swing on it," said Francona. "He's a good hitter. I told him the first week of the year that that's how this happens. You sit for a week and you don't play and then all of a sudden you're in there. This is why we got him.
"It's hard to find guys that can sit the bench and then they're good enough hitters to go in and play and get hits. I think we think he's one of them. And he has the attitude to match that and handle it. I think we're pretty fortunate. On the other hand, we're also fortunate we're able to send Youk over to third. I don't know how many teams can do that and feel comfortable."
Lowell, who was named the Most Valuable Player of the 2007 World Series, is off to a slow start this season. In 30 at-bats, he's hitting .200 and has yet to drive in a run.
Now, Lowell will put all his focus on getting healthy.
"I think these next three days are pretty important," said Lowell. "Hopefully if we can get all the swelling out in three, four days, I can start doing exercises and then maybe seeing if I could swing. We'll see. I'm kind of in limbo right now. I'm not really too sure."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.