Giolito will start Sunday's game against the Padres, Mark Zuckerman of MASN reports.
As expected, Giolito will come up from Triple-A after the Nats announced earlier in the week that Reynaldo Lopez had been demoted. Giolito has made two starts for the Nationals this season, allowing a combined eight hits and four earned runs, including two home runs, across 7.2 innings. He fared well in his only Triple-A start of the season, allowing one run over 6.2 innings, after amassing a 3.17 ERA across 14 Double-A starts. The Nats will need to make a corresponding move before officially recalling Giolito to the 25-man roster.