Player Highlight: Seattle Mariners Ace Luis Castillo

In this new series called Player Highlight, I will be choosing some random players throughout MLB to showcase their career stats and tell you how great they are. There are so many great MLB players that if they aren’t on your team you might never hear about. The first player is Luis Castillo. Castillo is a right handed starting pitcher for the Seattle Mariners. Castillo is a two time All Star. Castillo came over from the Cinnicinati Reds during the trade deadline in 2022. Castillo is one of MLB’s bright young pitching stars. Castillo had some up and down seasons before he really started to show that his stuff was elite at the MLB level. 

As you can see Castillo fluctuated early in his career, although he was able to keep his ERA below 4 in every season but 2018. (later we’ll dig deeper) After a rough 2021, Castillo was able to manage an ERA below 3. Castillo is a power pitcher with an ability to also get ground ball outs.  When he is at his best, you can see that in his low FIP, however his WHIP has suffered in years when his control wasn’t the best. At times, he’s been prone to walking a lot of batters. Setting aside all of that, when you look at his ERA+, he’s been just above or well above league average for a starting pitcher in every season except that bad 2018. Let’s look at how Castillo has transformed over the years.

In order to see how Castillo managed to take his 4.30 ERA in 2018 and turn it into a 3.40 in 2019, we have to see his pitch mix. You’ll under the number # of pitches how the amount of fastballs and changeups changes. In 2018, Castillo threw mostly fastballs but if you look at his put away % and Whiff % those are lower on his fastball at 12.3% and 19.6% respectively. This is compared to his changeup which had put away % and Whiff % of 30.7 and 42.8 respectively.  Obviously Castillo noticed this trend or a coach pointed it out to him so he changed up how much he uses each pitch in 2019. In 2019, his fastball and changeup were thrown nearly equally with only about 80 pitch difference. The put away % and Whiff % remained similarly effective for the changeup but still ineffective for the fastball. (Fastball whiff % did improve 8 percent) But 2019 was not Castillo’s best year, that was 2022. 

In 2021, Castillo Slider became much better but he still relied on the fastball/changeup combo. In 2022, Castillo really leaned into his fastball, which turned in the lowest WOBA of his career at .203. According to statcast, Castillo’s fastball velocity was in the 93rd percentile. Obviously there is more to pitching than just pitch mix, there’s location and movement. So to conclude, I want to preface his fastballs’ location and movement charts. Castillo’s velocity was earning him a lot of strikeouts and that’s due to his location. As for chase rate and fastball spin rate, Castillo only ranks in the 54th percentile and 60th percentile respectively. But you can see where batters chased his fastball according to this chart. In terms of spin rate you can see his fastball probably has the least spin of all his pitches. But the movement of his fastball on a similar par to his sinker. I think that Castillo has finally found a formula to keep striking out batters at a high rate but also limiting his walks. Castillo will definitely be key to the Mariner’s success in 2023. 

Thanks for reading! Be sure to follow or subscribe to the blog. Check out the social media page.

Thanks to Baseball Reference and Baseball Savant for the charts and statistics!