For the interim, Nick Green will be Boston's primary shortstop with Gil Velazquez -- who was summoned from Triple-A Pawtucket -- serving as the backup.
The injury to Lowrie came on suddenly. Francona wasn't made aware of it until Sunday, when, as a precaution, he sat Lowrie -- who is off to a 1-for-18 start. But after talking more with the switch-hitter, Francona realized that Lowrie's wrist issue was something that needed to be looked at by the team doctors.
Lowrie flew back to Boston, where he was examined Monday. The one reason the issue is of particular concern is because Lowrie played the last few months of 2008 with a small non-displaced fracture in that same wrist. That injury robbed Lowrie of his power from the left side, something that was no issue whatsoever this spring, when Lowrie was Boston's most productive hitter during the Grapefruit League season.
"They just want to get all their facts before they start telling us what they think is going on," Francona said. "He showed up yesterday and said it was bothering him. I think the more we started talking to him and pushing a little bit, we realized that we needed to get this thing checked out.
"He had such a good spring. Then when you kind of push and prod him a little bit, he had said that it had been starting to bother him for a couple of weeks but he didn't say anything. On one hand, we told him, 'Hey, you need to let us know.' But on the other hand, that's how players are. I guess you kind of respect it."
Green will try to take advantage of his sudden opportunity.
"As a competitor, you want to play," Green said. "You never want to see somebody get hurt. Hopefully he's fine. It's one of those things, I've got to be ready to play. That's my job. That's what I'm trying to do. You just have to be ready to perform if you do get the opportunity."
As for Lugo, he has been in Fort Myers, Fla., for the last few days ramping up his rehab. The Red Sox won't rush Lugo simply because Lowrie is hurt.
"His progression -- that can't change," Francona said. "There's a reason he's on that progression. He needs to stay at it. He'll probably get in a game here in the next three or four days, down [in Florida]. Even if a guy was progressing on a normal Spring Training without a knee surgery, I don't know if you can just play him two weeks in a row and expect all good things to happen. We've got to be a little patient there."