The Nationals claimed Waldron off waivers from the Blue Jays on Saturday.
Waldron has put up a 7.54 ERA and 1.62 WHIP over 37 innings in the majors this season between San Diego and Toronto, but the Nationals will pick him up anyway to add a multi-inning arm to their bullpen. Connelly Early (elbow) was transferred to the 60-day IL to create room for Waldron on the 40-man roster.