Ramirez experienced forearm tightness during his start Saturday, Maria Guardado of MLB.com reports.
This helps to explain his poor outing, but it's an ominous explanation. Ramirez underwent stem-cell therapy last season to treat a partially torn UCL in his throwing arm, and although it's unclear if this injury is related to that, it doesn't bode well for him. He'll be evaluated further Sunday, so more information should come forth then. It's unclear if he'll be able to make his next start, though things aren't looking good as they stand now.