Doolittle (elbow) has been transferred from Double-A Harrisburg to Triple-A Rochester, Jesse Dougherty of The Washington Post reports.
Doolittle holds a 3.86 ERA and 10:2 K:BB over seven innings across seven appearances so far in the minors as he works his way back from an internal brace procedure on his pitching elbow. The veteran reliever shouldn't need too many outings with Rochester before joining the Nationals' bullpen.