The Nationals designated Granillo for assignment Saturday.
Granillo has failed to impress over eight appearances with Washington this season, posting a 9.64 ERA, 2.25 WHIP and 3:8 K:BB over 9.1 innings. He hasn't fared much better with Triple-A Rochester, registering an 8.02 ERA, 1.66 WHIP and 32:16 K:BB across 33.2 frames spanning 26 appearances. Granillo will consequently yield his 40-man roster spot to Matt Krook, whom the Nationals claimed off waivers on Saturday.