Ryan Cook's stay in Reno was a short one.
The Aces sent the pitcher back to Visalia (Class-A) one day after he made his Triple-A debut in Reno.
Cook struck out five, but also surrendered six earned runs in five innings, picking up a no decision in the Aces 8-7 win over the 51s on Monday night.
Kevin Mulvey will take Cook's spot in the rotation. The Diamondbacks sent Mulvey down on Monday.