Diaz (illness) was participating in light baseball activities Thursday at the Pirates' spring-training complex, John Perrotto of DKPittsburghSports.com reports.
Diaz is slowly getting back into playing shape after a viral illness kept him away from camp for two weeks. The missed time will likely result in Diaz opening the season on the injured list, paving the way for Jacob Stallings or another non-roster player to begin the season as the Pirates' backup catcher.