The Diamondbacks placed Nelson on the injured list Wednesday without a designation, implying that he's been added to the COVID-19-related IL.
Outfielder/designated hitter Cooper Hummel was also placed on the COVID-19-related IL, with Arizona calling up infielder Yonny Hernandez and reliever Jacob Webb to take their spots on the active roster. Nelson has been a standout performer in the Arizona bullpen this season, gathering a win and five holds while posting a 1.23 ERA, 0.75 WHIP and 16:2 K:BB across 14.2 innings.