The Nationals called up Felipe Rivero from Triple-A Syracuse on Thursday afternoon.
Nationals reliever Craig Stammen will require surgery after an MRI Thursday revealed damage in his arm.
The Washington Nationals return home on Thursday to begin a seven-game homestand starting with a four-game set against the Philadelphia Phillies.
Ian Desmond's issues in the field highlighted a tough first week for the Nats. That and more on this week's Stock Watch.