Johnson said he's likely to stick with an eight-man bullpen.
"Probably, the next thing I'll do will be probably adding to it. That's in a month. But so far, we've been managing to get by."
Johnson said Jhonatan Solano's oblique injury is feeling "a lot better."
With the Nationals facing their second doubleheader in as many weeks on Friday, John Lannan will likely make his second start of the season. Lannan started the second game of the July 21 doubleheader with the Braves.