In case you haven't noticed, Kirby Yates has struggled at the major league level this season. He's only pitched 9.1 innings out of the bullpen, as he spent the beginning of the year on the disabled list, but over that one game worth of work he's posted an ERA of 7.71. That comes on the back of having given up five home runs out of 14 fly balls.
In his only other major league appearance (36 innings in 2014), Yates did not have trouble with the long ball.
Before I get any further into this, let's all acknowledge why analyzing 9.