Pomeranz left in the second inning of Friday's game against St. Louis with an apparent injury, Michael Silverman of the Boston Herald reports.
The nature and severity of Pomeranz's injury are not yet known. The 29-year-old has been fairly durable in the past two seasons, making at least 30 starts each year, though he did suffer a drop in velocity late last season, which sometimes is a precursor to an arm injury.