24 year old starting pitcher Vin Mazzaro was acquired from Oakland this past offseason and figured to be in the starting rotation. However, after a shaky start Sunday for AAA Omaha, manager Ned Yost is going to keep Mazzaro in the minors so he can continue to work out some kinks.

Mazzaro started at AAA because the Royals didn’t need a fifth starter until this Friday when Seattle visits Kansas City. Mazzaro just edged out Sean O’Sullivan for the number five spot in spring training and O’Sullivan stayed with the big league club in the bullpen.

Now, this Friday, O’Sullivan will get the start. “Sully can start in that spot, and we’ll give Vinny a chance to get settled in and get a couple of good games under his belt and then see where we’re at,” Yost said.

O’Sullivan hasn’t been particularly comfortable in his long relief role. In two games, giving up five runs in four innings for an 11.25 ERA.