Mariners’ starter Jason Vargas was named the A.L. Pitcher of the Month in July. The question always is though: “Was Vargas actually a different pitcher?” and “Can we count on him to be this good again?”. The initial guess is of course that Vargas has not changed. However, this is what advanced statistics and Pitch F/X are for.
So here we will look at all his starts in July and compare it to a couple of other Vargas starts in 2012.
Here how the pitches in that start broke in that start.
It is hard to see a real pattern in those starts. For example, he was really aggressive with his fastball on July 16th, but the two starts surrounding it have a lot less amount of fastballs in the strike zone. He pretty consistently throws his changeup low out of the zone other than his July 21st start. His cutter is incredibly different from start to start in terms of how he locates it. So lets compare how these starts look compared to some of his other starts.
Vargas’ worst start this year (in terms of FIP and xFIP) was against the Diamondbacks on June 24th:
Even in this start, you see a ton of changeups below the zone. However, as the pitch break graphic shows, they broke quite a bit differently. In his July 31st start, it broke a lot like his other pitches, but against the Diamondbacks, it broke distinctly unlike his other pitches. This may have allowed hitters to pick it up earlier and lay off it, making Vargas throw fastballs over the plate. It doesn’t appear that he threw more pitches down the middle than any of his July starts, but the hitters may have been able to sit on it more.
Most average start. Most Vargas according to FIP and xFIP start was probably on June 9th against the Dodgers.
The three top views given here all look different. His change in his most average start looks more like his change (at least from the top) from his worst start. Other than that it is hard to find a real difference in how he actually pitched. In his “average” start, his fastball was 88.94. For the year, it has been 88.84 MPH and was 88 MPH exactly in the last start of July. In his worst start, it was 88.05 MPH. So velocity obviously has nothing to do with it. So if we learned anything from our look at Pitch F/X, the success is all about his changeup. Is there another explanation though?
Perhaps defensive independent metrics will give us some insight. In his June starts, his FIPs were 3.96, 3.53, 8.92, 2.92, 2.96, and 2.37. That is a 4.11 FIP per start. So, especially because of the bad start, he hasn’t been exceptionally better than his career averages (4.47 career FIP). So really, he was a below league average starter for the month (league average ERA/FIP/xFIP is 4.03. League average FIP for starters is 4.13, so Vargas was slightly better than average). Over that time, he had an ERA of 1.64, suggesting that he had quite a bit of defensive help and/or luck. His SIERA over his June starts averaged 4.58, which isn’t very good at all. His ground-ball rate was much better than normal, with a 1.725 GB/FB (versus a career .81). However, his line drive rate was over 30 percent in 3 of those starts, which is terrible (league average is usually about 20 percent).
While monthly award are cool and I am sure they mean something to players, they don’t mean much when it comes to player evaluation. Jason Vargas did not really change. He pitched about normally and was really lucky and/or got help from his defense. Short sample sizes of statistics (especially basic statistics) shouldn’t change your views of a player. If Vargas has an ERA of 9.33 over his next 3 starts, it most likely doesn’t mean he changed. These are just the up and downs that come with long baseball seasons.