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# Gio Gonzalez effective velocity follow up

An analysis of Gio Gonzalez viewed through the lens of effective velocity.

Last week in this space, I examined Gio Gonzalez's consistent run of success. Gio is a pretty good manager of contact, and he is most certainly a strikeout pitcher. That's a combination for awesome. In order to dive a bit deeper, I turned to effective velocity to see if there were any illuminations I could see.

My method for calculating effective velocities goes as follows. Using Baseball Savant's PITCHf/x database, I gathered all pitches that Gio threw between 2009 and 2014 (so far) in the regular season. I split the dataset into lefties and righties to make accurate EV calculations. I divided all pitches* into a 5x5 grid similar to what Brooks Baseball or FanGraphs has. I was then able to calculate an effective velocity value for each pitch using this article from Baseball Prospectus.

*Thanks to Bill Petti for providing the zone coding.

There are a few tenets held by effective velocity that pitchers should employ to achieve maximum awesome. The first is that there is a danger zone and a safe zone of effective velocity values, with the danger zone representing better production for hitters. It appears that Gio spends 2/3 of his time in the safe zone.

Danger Safe
Righties 33.4% 66.6%
Lefties 35.8% 64.2%

Unfortunately, I have no benchmark at this time. I do not know what "league average" would be in this regard, but I plan to find out in the future. However, I imagine spending more than 50% of the time in the safe zone is a good place to start.

The second tenet is that hitters have a difficult time dealing with pitches whose effective velocity value is at least 6 mph different from the previous pitch. In order to get this value, I took the absolute value of the effective velocity difference from the previous pitch. I'm working under the assumption that whether the pitch is faster or slower doesn't matter. Gio does well in this regard. Gio's median absolute effective velocity difference is 6.7, but his mean absolute effective velocity difference is 8.4. Again, I don't know if the league on the whole is generally above 6 mph or not, but I plan to find out. Since there is a hard 6 mph cutoff, a league benchmark is slightly less important.

Most pitchers will have some degree of skew for this value; the minimum will always be 0 or very close to 0, but the maximum could be fairly high. In Gio's case, the maximum effective velocity difference he achieved was 32.9 mph, which he got through a change-up in a 2-1 count to Dan Uggla on 5/27/2012 in the bottom of the 7th inning.

Here is the 3rd pitch in the at bat before the aforementioned change-up. A fastball up and in, which adds effective velocity.

Here is the 4th pitch of the at bat. A "changeup".

Gio's heel actually dragged along the ground during part of his stride, which messed everything up. Gio stayed in the game to walk Dan Uggla on some more fastballs.

Unfortunately, the methodology I have right now is not perfect. The effective velocity value is irrelevant given the fact that the ball bounced about 2-3 feet in front of home plate. That's why median and mean values are important, and by those values, Gio is consistently confounding hitters.

. . .

All statistics courtesy of Baseball Savant.

Disclaimer: Kevin did not consult with Perry Husband about calculating these values, nor does writing about effective velocity represent an endorsement from Mr. Husband. Beyond the Box Score and Kevin are not affiliated with Perry Husband. You can find more information about Perry Husband and effective velocity here. In addition, Kevin used this article from Baseball Prospectus to help calculate the effective velocity values.

Kevin Ruprecht is a Featured Writer at Beyond the Box Score. He also writes for Royals Review. You can follow him on Twitter at @KevinRuprecht.