Frelick (side) could have played in Sunday's game and was held out as a precaution, Todd Rosiak of the Milwaukee Journal Sentinel reports.
This would seem to rule out a more serious injury like an oblique strain for Frelick, and he should be considered day-to-day for now. The Brewers face righty Brayan Bello in Boston on Monday, so the lefty-hitting Frelick could be back in action after sitting Sunday vs. a southpaw.