Hello Fish Tacos, Blake Snell Exclaims as He Joins Padres

On Sunday night, the Rays reportedly agreed to trade Blake Snell to the Padres for a collection of youngsters. With a career 3.24 ERA/3.91 SIERA, Snell makes for a strong addition to the Padres starting pitching staff. But aside from the potential change in offensive and defensive support, how might the switch in home park affect Snell’s results? Let’s check the park factors.

After spending his first five seasons with the Rays, Snell heads to the National League for the first time. Unfortunately, we still don’t know whether the DH will be in play in the NL again, so there’s the potential that the league switch could be a major positive if the DH ends up being just a 2020 thing. If the DH is back, though, then the league switch won’t have the same impact, and it will primarily come from the park switch and his team’s offensive and defensive support.

To begin, both parks have suppressed batting average, with Petco suppressing it slightly less than Tropicana. We don’t know how each park affects strikeout rate and BABIP specifically, but can still look at Snell’s marks to get an idea of how much each could potentially be affected. Obviously, Snell has been one of baseball’s best strikeout artists, as he has posted a strikeout rate of at least 31% each season since 2018. Those marks have been supported by strong SwStk% marks, which have finished no lower than 15% over that period. He has posted a meaningfully higher strikeout rate at home (30%) versus in away parks (26.6%), but the average starting pitcher is typically going to strike out a higher rate of batters at home. Given Snell’s high strikeout rate, he would be at risk of a park-related reduction, only because there’s clearly more downside than upside here. That doesn’t mean Petco is going to deliver that downside though.

On the BABIP front, Snell has been up and down, posting a mark as low as .241, and then following that up with an inflated .343 mark. It’s a reminder how random the metric could be. Overall, his career BABIP actually sits right around the league average at .293. Again, he owns a better home BABIP (.279) than away BABIP (.306), so it’s something to consider, though it doesn’t mean it will rise in a new ballpark.

Though Petco is slightly less batting average suppressive, it’s actually slightly more suppressive for singles. On the other hand, Petco is a bit less pitcher friendly than Tropicana for doubles, but significantly more pitcher friendly for triples.

Last of the hit type factors, and perhaps most importantly, Petco has inflated home runs, while Tropicana has deflated them. Snell’s HR/FB rate spiked in 2019, but then skyrocketed to an insane 29.4% during the shortened 2020 season. Overall, his career HR/FB rate sits at 12%, which is well below the league average during the period. Once again, we find much better results at home (10.6% HR/FB rate) than away (13.4% HR/FB), suggesting he possibly benefited from Tropicana’s park effects, over and above the typical home field benefits a starting pitcher would realize. The move to Petco should probably raise your HR/FB rate projection, leading to an extra home run or two.

Because of the higher HR park factor, Petco’s SLG factor, while neutral, is higher than Tropicana’s, which is slightly pitcher friendly. Since the majority of SLG is composed of doubles and home runs, both of which Tropicana is better at suppressing, we know the park switch might lead to more extra-base hits against Snell, which is a clear negative.

Finally, we arrive at our aggregate offense park factors, both of which are close, but do favor Tropicana. While Petco reduces wOBAcon, or wOBA on contact, it has reduced the rate by a slightly lesser degree than Tropicana. Furthermore, Petco has been neutral in its effects on RBIcon, or estimated runs scored on contact, while Tropicana has been slightly suppressive. These metrics simply summarize what we’ve already discussed, but would also include effects on walk rate, which we don’t have factors for, among other things.

Overall, the park switch by itself is a clear negative, but not by a significant degree. The majority of the effects might be seen in Snell’s HR/FB rate, which would result in a couple of more home runs, and of course runs allowed. There are likely bigger factors here that should influence his value, such as expected offensive and defensive support, and how quick a hook the Padres will give him (which Sporer dove into yesterday). Snell has actually averaged fewer than five innings a start since 2019, as the Rays opted to utilize their deep bullpen. Odds are, the Padres allow Snell to pitch deeper into games, which would increase his strikeout total and win potential. However, it could result in a higher ERA and WHIP.