Report: Medical issue delaying Martinez announcement with Red Sox

The cause of the delay in the Boston Red Sox officially announcing the signing of J.D. Martinez reportedly involves concerns surrounding the future health of the slugger.

The two sides agreed on the framework of a five-year, $110-million deal Monday but have been processing the results of a physical since then. While the issue isn't known, it's not believed to have any effect on Martinez currently and more information will likely be revealed Saturday, a source told Evan Drellich of NBC Sports. He adds that additional medical experts have been involved and that the process remains cooperative.

Boston is apparently practicing caution by taking additional measures to ensure it's protected financially in the event of an injury, according to the Boston Globe's Pete Abraham, whose sources also tell him Martinez does not have an injury that would prevent him from playing this season.

The Red Sox have maintained throughout the week that there is no concern the deal will not be completed and that the club is just being thorough with reviewing the medicals.

"All I can say is that he continues to take his physical," president of baseball operations Dave Dombrowski said Thursday, according to Scott Lauber of ESPN.

"I'm not concerned," Red Sox manager Alex Cora told reporters Friday after the team's spring opener.

Martinez is believed to have an opt-out clause in his contract after year two of the deal, and the Red Sox will likely want to ensure his body will hold up throughout the course of the five-year contract should he remain with the team.

While Martinez is among the league's elite hitters, he has had issues staying on the field throughout his career. He's appeared in more than 150 games just once in his seven years in the majors, and missed 85 games over the last two seasons due to a foot sprain and fractured elbow.