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ALCS Coverage: Jepsen’s Stuff (and Other Notes)

Posted By Carson Cistulli On October 18, 2009 @ 5:14 pm In Daily Graphings | 18 Comments

Wow. (Or as the young women of the Greater Los Angeles area might say: Wowskis.) That was a great baseball game.

One day after I wrote about the rather predictable nature of Game One, this happened:

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Some facts you might like to know about the game in question:

* The average Leverage Index (aLI) was 2.07. That’s higher than the Game 163 I used last time as, like, the platonic ideal of excitement. (It occurs to me now — as it should’ve done already — that an extra inning game will almost by definition feature more high-leverage situations. So I ask myself: Are extra inning games better than nine inning ones? Not as a rule. I mean, I’ve definitely seen some dull extra inning games.)

* Alex Rodriguez recorded both the highest and lowest single WPA plays of the evening. His home run off Angels reliever Brian Fuentes in the bottom of the 11th inning was worth .429 WPA. In the very next inning, he recorded a -.165 WPA when he flew out to center off Ervin Santana with two out and the bases loaded.

* Mariano Rivera recorded the highest total WPA: a mark of .393 in 2.1 innings of excellent high-leverage work.

On Kevin Jepsen

I’ve been meaning to set aside some space for Jepsen in this Angels playoff coverage, but’ve failed to do so. Well, some of the things he did in last night’s game made it hard to ignore him any longer.

For example, you might remember that, after Jepsen’s first offering to Jeter in the eighth inning, he (i.e. Jeter) stepped back from the plate, eyes wide and smiling a bit, and said something along the lines of, “Wow.” That pitch was Jepsen’s cutter — his only one of the night, actually. But Jepsen has thrown it about 25% of the time this year and recorded a 1.48 wCT/C on it. It’s been his main complement to the four-seam fastball.

After the cutter, two such four-seamers followed. They were both balls, but both featured about 13.5 inches of upward movement, a little over four inches of horizontal movement (towards Jeter), and were thrown at 96.6 and 96.5 mph, respectively. Not bad.

The last two pitches were excellent. The first (and fourth of the PA) was a fastball very similar to the two that preceded it, except basically right over the plate. It had a little less vertical movement (12.5 inches) than the two before it, a little more tail (-5.2 inches), and came in at 98.5 mph. Jeter swung and missed.

Finally, with the count at 2-2, Jepsen threw a slider. A nasty one. And even though, like many sliders, this one registered what seems like little movement (2.1 inches of x-movement and 1.7 inches z-movement), it makes more sense to look at pitches like these in context, I think. In particular, it makes sense to look at the break of a pitch as compared to its pitcher’s fastball.

In this case, we know the break of the fastball Jepsen had just thrown (12.5 x-inches, -5.2 z-inches). If we take the absolute value of (slider x-movement minus fastball x-movement) and also the absolute value of (slider z-movement minus fastball z-movement), we get something we can call Total Movement Delta (TMD). In this case the TMD of Jepsen’s slider to Jeter as compared to the fastball that immediately preceded it was 18.2 inches — for a pitch that was recorded at 89.9 mph by GameDay. By comparison, among the pitchers who threw at least 50 IP this year and threw the slider at least 2% of the time, the highest average velocity of said pitch was 90.0 mph even, recorded by Angel Guzman. Next on the list is Brandon Lyon at 89.2 mph. So Jepsen’s was up there, is the point.

And the larger point is, of course, is that Jepsen threw a pitch that was both (a) real fast and (b) had a ton of movement. That Jeter swung and missed is hardly surprising.


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