Sheehan (shoulder) completed a bullpen session Sunday, Fabian Ardaya of The Athletic reports.
Sheehan was able to get back on the mound for the first time since he experienced shoulder soreness shortly after reporting to spring training in late February. Manager Dave Roberts already noted Saturday that Sheehan will start the season on injured list, but the young right-hander's ability to throw a bullpen session Saturday offers hope that he'll avoid an extended absence. With Walker Buehler (elbow) expected to join Sheehan on the IL to begin the campaign, Gavin Stone looks to the frontrunner for the No. 5 spot in the Los Angeles rotation.