Madison Bumgarner is still the San Francisco Giants Ace

2017: The Year of the Cutter

There has been a lot written about Madison Bumgarner and his “decline”. A lot has been made of his dip in fastball velocity, his hard hit percentages, and barrel rates as reasons to believe that Bumgarner’s best years are behind him. However, Madison Bumgarner is a 29-year-old pitcher, not the family dog.

Bumgarner definitely doesn’t look like a player who should be “sent off to a farm upstate”. Even Bumgarner said in a recent interview with Henry Schulman of the San Francisco Chronicle that coming back too soon from injuries could have contributed to his dip in velocity. That theory could also be applied to his ability to locate his pitches, which could justify the uptick in barrel rates and hard hit percentages.

The 2017 season was a lost season for the Giants. Even before Bumgarner hit the disabled list by getting into a pretty cool (or uncool depending on who you ask) dirtbike injury, the Giants were not off to a good start. The Giants were 6-11 when Bumgarner hit the DL April 21st and were 35-57 when he returned from the DL July 15th. Although, it seemed like a lost season, Bumgarner seemed to use it as an opportunity to experiment. In the previously mentioned article, Bumgarner mentions feeling like his velocity was “normal” prior to the dirtbike incident. Pitch/fx backs that up. Below is a table of Bumgarner’s average fastball velocity throughout the 2017 season.

As the Giants season continued to be a proverbial dirtbike crash and Bumgarner tried to remain effective despite his drop in velocity, he used it as an opportunity to work on his cutter. For the majority of Bumgarner’s career he featured a “slider”, but for whatever reason Statcast started classifying this pitch as a cutter in 2017. So, cutter/slider, hereafter this pitch will be referred to as a cutter. Bumgarner ended up throwing his cutter a lot. He started the season throwing fastballs to cutters at roughly a 2:1 ratio and by the end of the season he was essentially throwing one cutter for every fastball. Here is a table noting Bumgarner’s 2017 fastball to Cutter use according to Pitch/fx.

You can see based on Bumgarner’s much heavier usage of cutter from August and September 2017, that his cutter overtook his fastball as his primary pitch. Weather he felt more comfortable throwing his cutter because of his decreased velocity or he made a conscious decision to make his cutter his primary pitch, the numbers indicate there was a concerted effort to throw more cutters.

Another interesting correlation from his 2017 numbers is that Bumgarner had his worst month statistically in September. Going back to the first table you’ll find that Bumgarner’s biggest difference in velocity between his fastball and his cutter was also in September. Perhaps the effectiveness of Bumgarner’s cutter is dependent on the difference in velocity with his fastball.

When his cutter velocity is within roughly 4 mph of his fastball as it was in April, July and August 2017 he was his most effective. When the difference in velocity increased to a 5+mph in September, Bumgarner didn’t seem to be as effective. I can’t say for a fact this is the reason that Bumgarner struggled in September of 2017 compared to the other months, but it could speak to the effectiveness of his cutter. Perhaps, the closer his cutter is in velocity to his fastball, the more deceptive his cutter is, therefore his cutter is more effective. This is just a theory, but it is my theory, so I am probably right.