Martinez's signing with the Red Sox has been delayed by a medical matter, Evan Drellich of NBC Sports Boston reports.
It's expected that more information regarding the undisclosed medical issue will surface later Saturday, but a baseball source with knowledge of the situation said the medical issue would not have an impact on Martinez's immediate future. Additional medical experts are involved as the team and Martinez work through the issue, including experts consulted by the player's agent, Scott Boras. The source described the process between the team and player as cooperative.