Manager Mark Kotsay said Wednesday that Irvin is being evaluated due to shoulder soreness, Matt Kawahara of the San Francisco Chronicle reports.
While the left-hander hasn't yet been ruled out for Friday's start against Minnesota, Zach Logue has been added to the Athletics' taxi squad in case Irvin is unable to pitch. Kotsay said the Athletics will decide Thursday whether Irvin is able to take the mound during Friday's matchup, so he should tentatively be considered day-to-day.