Seven weeks ago, after a physical revealed the existence of a degenerative bone condition in both of Mike Napoli's hips, the Red Sox insisted on greatly reducing the terms of his contract.

Yesterday, they acquired additional insurance.

The Red Sox reached an agreement with veteran first baseman Lyle Overbay on a minor league deal that includes an invitation to spring training, a source told the Herald. If Overbay is not added to the 25-man major league roster before Opening Day, he may opt out of the contract and sign with another team.

At a minimum, Overbay could potentially offer protection for the Red Sox in case Napoli begins experiencing problems related to avascular necrosis, a disease that results in deterioration and possible death of a bone in the hip caused by a lack of blood flow. But the 36-year-old also could serve as a left-handed bat off the bench and a late-inning defensive replacement for Napoli.

All along, the Red Sox have been on the lookout for a left-handed hitter capable of playing both first base and left field, a search that is expected to continue throughout spring training even after the deal with Overbay. But the need for greater depth at first base has become more urgent since Napoli's hips began getting even more attention than Shakira's.

It's worth noting that Napoli is asymptomatic and has been taking medication to maintain that status. Napoli was signed to be the Red Sox' primary first baseman, and general manager Ben Cherington has expressed confidence that the slugger can stay healthy this season.