Jansen was visited by trainers due to back stiffness in his appearance against the Guardians on Saturday, Christopher Smith of The Springfield Republican reports. He allowed one run on three hits while blowing his first save of the season with no walks and a strikeout.
Jansen was visited by the trainers in the ninth inning, and while he was able to continue in the outing, it clearly was bothering the right-hander. Jansen threw 29 pitches in his outing Saturday, so he likely won't be an option for the Boston bullpen regardless of how his back feels Sunday. John Schreiber seems like the best bet to get a save opportunity in games Jansen is unavailable.