The Padres reinstated Waldron (forearm) from the injured list Saturday.
A forearm strain has kept Waldron on the injured list since mid-May, but he has been playing in rehab games at Triple-A El Paso since June 14. The 29-year-old gave up four earned runs while striking out 10 batters in 15 innings across five appearances during his time in the minors. The Padres don't currently have a spot open for him in the rotation, so he figures to work out of the bullpen as a long reliever for the time being.