The Nationals recalled Solis from Triple-A Syracuse on Friday.
He takes the place of Enny Romero, who was placed on the 10-day disabled list with a left forearm strain. Solis is saddled with a 14.00 ERA over nine innings with the Nationals but was lethal in 2016 (2.41 ERA, 10.3 K/9, 4.6 BB/9 in 41 frames). Perhaps he'll reclaim a steady role in important middle-inning appearances.