The Giants placed Harrison on the 15-day injured list, retroactive to Wednesday, due to left shoulder inflammation.
Harrison was roughed up in his last outing Tuesday against the Diamondbacks, when he allowed six runs on seven hits and one walk while striking out three over 2.2 innings. He's given up 11 runs over his last two starts, and since the beginning of August he's posted a 7.76 ERA and 1.57 WHIP across 26.2 frames. Harrison will be eligible to return from the IL in mid-September, though it's unclear whether the injury is severe enough to shut the 23-year-old southpaw down for the rest of the season. Austin Warren was recalled from Triple-A Sacramento in a corresponding move.