"Bobby actually had a small pulmonary embolism," manager Terry Francona said Tuesday. "Through the course of all this testing they were doing on his back, they found a pulmonary embolism, which is certainly nothing to mess around with. There just needed to be a lot of testing. Bobby was put on proper medication, and that's probably going to slow down the efforts to look at his back a little bit. But in a hurry, the back becomes secondary. Bobby's doing fine, he's on proper medication, he's doing great."
A pulmonary embolism occurs when one or more arteries in the lungs is blocked, according to the Mayo Clinic's website. In most cases, they're caused by a blood clot traveling from another part of the body into the lungs.
"I don't believe so," Francona said when asked if the injury is career threatening. "This was a very small -- I mean, [this is] still nothing to mess around with, but it's a very small -- embolism. They have it under control. Certainly, they want it to go away, but I think they feel that he's in good shape."
Bothered by his back most of the year, Jenks hasn't pitched for the Sox since July 7. In the first season of a two-year deal, he made just 19 appearances.
Hall of Famer Tony Gwynn is an advocate for awareness for deep vein thrombosis, a condition that can lead to pulmonary embolisms.