The Nationals will select Baker's contract from Triple-A Rochester on Sunday, Spencer Nusbaum of The Washington Post reports.
MLB rosters will expand from 26 to 28 players Sunday, so the Nationals will take the opportunity to add depth to their bench by promoting Baker. The 25-year-old has spent the entire season at Triple-A slashing .285/.348/.340 with 49 RBI across 483 plate appearances. While he may not offer much in terms of production at the plate, his ability to play both second base and left field will give the Nats additional defensive flexibility for the final month of the season.