Charlie Morton Travels North On Route 75 to the Braves by Mike Podhorzer December 7, 2020 Back on November 24, Charlie Morton signed a one-year deal with the Braves, as he makes his return to the National League, where he last pitched back in 2016. Of course, back then things were quite a bit different, like no designated hitter, which is something we expect to remain permanent in the NL moving forward. So there is now little different between leagues, and Morton’s isn’t going to get any boost, since he won’t be facing a pitcher at the plate. That said, let’s dive into the park factors to see how the park change might affect his performance. Park Factor Comparison Park AVG 1B 2B 3B HR SLG wOBAcon RBIcon Tropicana Field (Rays) 98 99 97 107 97 98 98 98 Truist Park (Braves) 100 101 102 91 96 99 100 98 SOURCE: RotoFanatic.com I highlighted the more pitcher friendly factor for each statistic. The RotoFanatic park factors are three year factors, but haven’t been updated yet for 2020 (though with such a small sample size, I’m not sure I want them to be updated!). So these represent 2017-2019 park factor calculations. So let’s start at the beginning. Tropicana slightly suppresses batting average, while Truist is neutral. Unfortunately, we can’t be sure what’s driving the difference in batting average park factor, as it could be a reduced BABIP at Tropicana, or perhaps more strikeouts. Maybe a bit of both. Whatever it is, it’s a minor negative for Morton heading into the neutral park versus the marginally favorable park. Moving along to the hit type stats, we find a mixed bag. Tropicana slightly reduces singles and doubles, while Truist slightly inflates both hit types. Since those are the two most common hit types, it makes sense that if Tropicana is more pitcher friendly for those, then the park would be more batting average friendly. So it looks like it’s mostly a BABIP thing driving that 98 batting average park factor. Tropicana isn’t more pitcher friendly than Truist in every hit type, though. Truist significantly suppresses triples, while Tropicana has inflated them by nearly the same degree. Of course, triples are the least common hit type, so that’s not going to make much of a difference. Finally, we arrive at the home run park factor. Morton used to be an extreme ground ball pitcher, but that rate has come down significantly over the years, so home run park factor actually matters far more than it had for him in the past. The two parks are nearly identical, but Truist has actually suppressed the long ball slightly more than Tropicana. While that would be a good thing for any pitcher, Morton hasn’t exactly struggled to keep his fly balls in the park, as his HR/FB rate has been well below the league average since 2019. The previous couple of seasons, he bounced around the league average, sometimes ending below it and sometimes just above. The park factor difference here is small though, so noise and randomness are going to be much larger influences on his 2021 HR/FB rate than the change in home park. Still, it’s good that he isn’t going to a home run inflating park. Now we move on to SLG, or slugging percentage, which essentially just aggregates the hit type factors into one number. Once again, we find the two parks nearly identical, with Truist being a bit less pitcher friendly. Next is wOBAcon, or wOBA on contact, which only counts wOBA when the ball is hit into play. Here, we find Tropicana with a slightly larger lead, though it remains small. Truist has been exactly neutral, so it ain’t so bad for Morton, as at least he isn’t moving to a hitter friendly environment. Last is RBIcon, which is expected RBI on contact. The site itself suggests using this factor as a proxy for the park effect on a pitcher’s ERA. After discussing all the hit type factors and some of the aggregates, we ultimately learn that these two parks are basically identical, both sporting 98 RBIcon factors! So the park switch itself shouldn’t have any impact on Morton’s performance. The real issue with Morton is his age and fastball velocity. He’ll be entering his age 37 season and opened his 2020 season with his velocity well down from 2019. He then hit the IL with shoulder inflammation, which was likely bothering him in those four starts leading up to the IL stint. Sure enough, he returned about three weeks later and his average fastball velocity was up 1.8 MPH from his last pre-IL stint start. That proved to be the highest game velocity he recorded the rest of the way though, as his velocity then regressed a bit, but remained above his pre-IL stint starts. So the good news is that his velocity did rebound somewhat after returning from injury, which provided a clear explanation for the dip in the first place. The bad news is that in three of his five starts after returning from the IL, his velocity was still down (though not to the degree as earlier in the season), so it’s anyone’s guess what we’ll get from him in 2021, especially now that he’s many months older.