What Has Changed for Jake McGee?


New season, new Jake McGee. In 2011, the lefty McGee struggled the entire season, spending time at Triple-A and posting just a 4.50 ERA and a 4.70 FIP in the big leagues. He showed off his plus stuff with an 8.7 K/9 but he walked 3.9 batters per 9 innings and allowed a ghastly 1.6 HR/9. He allowed flyball after flyball, managing just a 32.5% groundball rate, and he payed dearly in terms of the longball. But in 2012, it has been a completely different story. McGee’s ERA and FIP have free-falled to just 1.77 and an even-lower 1.58 respectively entering Wednesday as he has upped his K rate to 10.6 per 9, cut his BB/9 to 2.7, and not allowed a single home run- a fluke but not as much as you would think because his groundball rate has gone up to a much more respectable 42.9%. The stats are certainly a lot better. But is there a noticeable difference in his pitches that has led to the better performance? We go to the graph, which features Pitch F/X data courtesy of Brooks Baseball in my original display.

Haven’t done one of these in a while, so here’s a quick refresher course. These graphs display the movement on a pitchers’ pitches, in this case Jake McGee. Each colored line in the graph displays the movement of a different pitch. Looking at the key tells you which pitch is which, how often each pitch was used, and what the pitches’ average velocity was. It terms of visualizing the lines, picture them as if you’re in the batter’s box and they’re coming towards you or alternatively, each pitch moves approximately the same distance from the pitcher’s mound until it crosses the plate (other than say 58-footers), and we’re ignoring that to just look at the vertical and horizontal movement. For a more detailed information on this and on the entire concept of Pitch F/X as whole, you can see here.

Now, let’s analyze this. The first thing that stands out is the key. McGee scrapped the pitch that Pitch F/X identified as a curveball, instead throwing his fastball and slider a little more and mixing in his changeup a couple of times. McGee’s movement on his fastball and slider looks about the same, maybe a little more horizontal movement and a little less downward movement on his slider. But the big difference is velocity. McGee’s fastball velocity has been up a bit, jumping from an average of 95.6 MPH to 96.1 MPH, not a huge difference but certainly noticeably for opposing hitters. But look at the slider. McGee is throwing it nearly 3 MPH harder, 87.2 MPH to 84.4 MPH. What has that done? It has helped him control it better because it has moved a little less. McGee’s fastball control has been about the same as he has located it in the strike zone right around 70% of the time. But his control of his breaking ball has improved astronomically, throwing it for a strike 58% of the time compared to just 41.5% in 2011.  There is just a 4.7% chance that type of improvement would occur by chance alone. His improved control of the pitch has helped him spike his whiff rate on the pitch from 5.7% to 12.0%. And that in turn has helped his fastball. There is another, more subtle thing as well: if you look carefully at the graph, you can see that the lines for the fastball and slider in 2012 start almost identically compared to being just slightly off in 2011. That little bit of deception just makes him slightly tougher, and he’s hard enough to hit right now.

We have known for a while that Jake McGee has outstanding stuff. But in 2012 he has tightened everything up and the results have been incredible. Jake McGee has the ability to be a closer someday. If his stuff continues to be as sharp as this, someday will come sooner rather than later.