The Nationals optioned Eder to Triple-A Rochester on Friday.
Eder has pitched 6.2 frames this spring in Grapefruit League play, yielding four runs (two earned) with a 6:6 K:BB. The left-hander will likely be part of Rochester's rotation to begin the season, but all nine of his big-league appearances have been out of the bullpen. He could fill either role with the Nationals when called upon.