Tomorrow is the first day teams could expand their rosters, but the Nationals will wait to add a small wave of players until the minor league season ends Sept. 5, Manager Davey Johnson said. That does not include starting pitcher Tom Milone, who will make his major league debut Saturday.

Here’s a quick rundown of likely additions aside from Milone and Chris Marrero, who joined the Nationals over the weekend when Ryan Mattheus went on the disabled list:

-Brad Peacock, RHP, 23: He blossomed from the very start of this season, harnessing a fastball that travels as fast as 97 miles per hour. He won the Eastern League pitcher of the year award, and in 25 appearances between Class AA Harrisburg and Class AAA Syracuse, Peacock has gone 15-3 with a 2.39 ERA, 177 strikeouts and 47 walks.

-Atahualpa Severino, LHP, 26: The Nationals are high on his potential as a lefty out of the bullpen because of how much movement he gets on pitches. He has been called to the majors twice, but has never appeared in a game. Severino had his season shortened by injury and has posted 37 strikeouts and 22 walks in 30 2/3 innings this year in Syracuse.

-Roger Bernadina, OF, 27: Bernadina spent much of this season as the Nationals’ starting center fielder but was shipped to the minors after the Nationals traded for Jonny Gomes just before the July 31 trade deadline.

-Stephen Lombardozzi, IF, 22: Since a midseason promotion to Class AAA Syracuse, Lombardozzi, a Columbia, Mary., native, has hit .320/.364/.426 in 64 games.

-Yunesky Maya, RHP, 30: Maya joined the Nationals’ rotation while Tom Gorzelanny was on the disabled list in late May, and he also made one spot start the day the Nationals traded Jason Marquis, going 1-1 with a 5.40 ERA in the majors this year. Maya signed a four-year, $6 million deal with the Nationals last season after defecting from Cuba.

Those expected moves will force the Nationals to trim some players off their 40-man roster. Milone, Lombardozzi and Peacock are not on the Nationals’ 40-man roster. Plus, Stephen Strasburg will be coming off the 60-day disabled list.

The Nationals can make room for two of them by transferring Adam LaRoche and Cole Kimball to the 60-day disabled list, but it looks the Nationals will have to designate two other players for assignment.