Welcome back to Week Three of the GPS Location Report. My in-depth dive into location-based analysis for pitchers. In the first edition, we looked into Dylan Bundy and he promptly went out a threw a gem. The two starts after have not been as dominating but Bundy has still taken a step forward and is someone who is a must-start in fantasy leagues.
Last week I looked into the struggles of Jose Berrios, mainly due to the poor results of his fastball. The bad numbers were mostly deserved based on location and he seemed to take a different approach this time out. The right-hander used more breaking balls than fastballs and had his best outing of the season. Hopefully, this week my dive into a budding Marlins’ ace leads to a similarly dominant performance.
Making his debut back in 2018, Pablo Lopez looked like he was talented enough to be a serviceable back end of the rotation type of pitcher. He didn’t dominate with strikeouts and had some homer issues but he was able to limit walks enough to be somewhat successful. 2019 looked the same on the surface but a poor LOB% rate led to an ERA over five. His peripherals seemed to view him as the same pitcher as he was in 2018. However, my StuffERA metric seemed to be more of a fan of him than FIP was. The main thing that it saw was a pitcher who had a small ability to suppress wOBA.
This year, Lopez has taken a massive step forward. The two biggest changes with respect to his underlying numbers are a big jump in Ks and a big jump in GB rate. Both of these are significant improvements and take Lopez into special air. Among the 19 pitchers with over 50% GB rates (Lopez is at 60), he is one of six pitchers with a K/9 over 9. The first question to ask is what has changed.
As we can see from the chart above the changes are pretty jarring. Lopez is throwing a ton more change-ups and has traded some fastballs for sinkers. That last point likely helps to explain the big jump in GB%. However, not much seems to explain the change in strikeouts. Typically, the first thing I like to look at when it comes to big changes in K rate is changes in expected whiffs according to my model. However, Lopez does not appear to be any different here. Typically, Lopez posts an expected swinging strike rate of around 10% and this has not changed at all. Yet his actual observed swinging strike rate is 14%.
Typically, changes this massive are not normal however, I think the pitch mix change helps to explain this. Sinker ballers grade poorly in the expected whiff model due to the location of sinkers. Fastballs up in the zone tend to lead to more whiffs and down in the zone lower expected whiff numbers. Sinkers by nature are thrown down. Lopez is also throwing a ton more change-ups though. As you can see from the chart below he has been elite with his locations.
Almost every single one of his change-ups thrown has been in the red zones, which are high whiff locations. Among the over 100 pitchers who have thrown at least 50 offspeed pitches, Lopez has the 19th highest expected swinging strike rate on those pitches. However, the actual swinging strike rate on the pitch is the 5th highest in the same sample. So this leads me to believe that the pitch itself is elite for Lopez. The increased usage of the pitch can be the explanation for the massive jump in the actual observed swinging strike rate compared to the expected results. This jump coupled with the likely drop in expected rate due to the increased sinker usage may have led to his expected swinging strike rates appearing identical to previous seasons.
As long as Lopez continues to throw his change-up in all counts and can continue to generate ground balls through the use of his sinker I think he may be a guy that we are considering as an SP3 next offseason. This is a truly legit improvement backed up by impressive underlying numbers.
Stuff ERA Leaders
All stats are updated as of Sunday, August 22nd.
|Min 250 Pitches|