Greg Holland has had a great start to the season since being called up on May 19th. In 20.2 innings of work (all data does not yet include Wednesday's game), he has a 2-1 record, an ERA of just 1.31 and K/BB of 4.17. With stats like these, he looks to be lights out and digging a little deeper into his performance so far this season shows that it it isn't "all" smoke and mirrors.
The Bad News
All is not rosy with the 25 year old. First he has a BABIP of 0.234. Relievers will generally have a lower BABIP than starters, but this level can not be maintain. Another stat that will go down as his BABIP rises is his 93% LOB% (~70% is league average) which will lead to a higher ERA.
Another area of concern is his ability to continue to get players to chase and miss pitches out of the strike zone, specifically with his slider. Right now, he is getting hitters to swing at 36% of the pitches out of the zone (lg avg = 30%). More importantly, the hitters are making contact on only 41% of the on these pitches (lg avg = 68%). This ability to miss bats can be seen by a 51% swing and miss rate on his slider. These numbers are outstanding, but hitters may learn to lay off the slider as they become more familiar with him thereby decreasing his swinging strikes and strikeout rate.
That is about it.
The OK News
His ground ball % (40%) and HR/FB% (10%) are not a concern right now since they are near the league average.
That is also about it.
The Good News
First he is striking out quite a few number of hitters. Of the 351 pitchers that have thrown over 20 innings, his 10.9 K/9 ranks 16th in the league (Zack is 12th and the highest ranked starter). The value could actually go up. His Swinging Strike % is at 16% which ties him for 4th in the league. Normally a player's K/9 = SwgStr% - 1.5 which would put his K/9 near 13.5 K/9.
To go along with the strikeouts, he is not walking many batters as seen by his 2.6 BB/9. The high Ks and low BB has lead to a decent FIP (2.65) and xFIP (2.52). These values are higher than his ERA, but are still respectable.
Right now Greg is throwing great and the numbers back it up. I am concerned a bit that the league may catch up with him, but the Royals should ride The Flying Dutchman as long as possible.