Poulin will serve as the Nationals' opening pitcher in Friday's game against the White Sox, Mark Zuckerman of NatsJournal.com reports.
It will be Poulin's fourth opener assignment this season. He's preceded Miles Mikolas for the last two of them and that will likely be the case again Friday. Poulin holds a 4.97 ERA and 8:8 K:BB over 12.2 innings this season.