Justin Turner is Shipping Up to Boston

After nine seasons with the Dodgers, Justin Turner signed a two-year contract with the Red Sox on Friday. Even during his age 37 season, Turner could still hit, so he should see the majority of the team’s DH PAs. How might his new park affect his performance? Let’s consult the park factors.

Surprised? I am somewhat, as I didn’t expect Fenway to be nearly a clean sweep in favoring hitters. There’s one factor in particular I’m also surprised about for Dodger Stadium. Let’s dive in.

We’ll start with the hit type factors as usual. No need to separate them out, Fenway easily wins the trio of non-home run hit type factors. The Green Monster and quirky outfield dimensions make it BABIP heaven for hitters, so on average, hitters will see their singles, doubles, and triples rates increase while playing there. This is opposite Dodger’s effects, as it actually suppresses every non-home run hit type.

We could see from Turner’s splits that he seemingly was effected by Dodger’s BABIP-suppressing effect. During his time with the Dodgers, he posted a .316 BABIP at home, but a .322 mark away. Since hitters usually hit better at home, that’s a meaningful split. Also note that Turner has been an above average BABIP guy for much of his career. He sports a career mark of .315, thanks to a high line drive rate and low IFFB%, despite being a fly ball hitter. There’s a real chance he flirts with a new career high BABIP over a full season, as his current best over a reasonable sample size sits at .334.

We next move to the home run factors, which really surprise me. Did you realize Dodger Stadium was the third friendliest park for right-handed home runs this past season?! I did not. The change to a serious home run park began in 2019 and then it inched higher in 2020 and has remained there since. This is quite the change from being a pitcher friendly home run park back in the mid-2010s.

So if we look at Turner’s HR/FB rate splits beginning in 2019, we see these park factors having their impact. He has posted a 14.7% mark at home, but just a 10% mark away. He seemingly has benefited from Dodger’s recent transition to boosting right-handed home runs. Fenway, on the other hand, is closer to neutral. Given these factors, Turner’s HR/FB rate forecast should decline upon this move.

Let’s now get to the strikeout and walk factors. The strikeout factors are fairly similar, though oddly Turner has struck out at home more often. There’s a wide gap in he walk rate factors, though, as Fenway is neutral, but Dodger dramatically suppressed them last year. Turner has walked more often on the road, so he has struck out more, and walked less at home. The move to Fenway should bump up his walk rate projection.

We next move to the batted ball type factors. As mentioned earlier, Turner has become an extreme fly ball hitter, and has posted a mark over 40% every season since 2016. He has also kept a LD% above 20% every single season of his career, which is quite impressive. Just once did it even dip below 21%. Fenway increased ground balls, versus a reduction by Dodger, while the fly ball factors are fairly similar. Turner has hit a higher rate of fly balls at home than away during his Dodgers career and a slightly higher rate of grounders in away parks. Furthermore, we see that Dodger suppressed liners, and discover that he has posted a significantly higher mark on the road. So his batted ball type splits do match the factors.

While we can’t be sure if Fenway itself will cause Turner to alter his swing or something else is at work, we might want to bump up his GB% and LD% and reduce his FB% slightly. Remember, these adjustments help explain why Fenway is such a strong BABIP park.

Finally, we arrive at the Basic run scoring factor. With its BABIP-boosting ability and above average home run factor, Fenway is a runaway hitter’s park. This compares to Dodger, which is overall a pitcher’s park. Keep in mind, though, that the Basic factor accounts for hitters from both sides of the plate, while the hit type factors only account for right-handers. The park’s left-handed home run factor was significantly lower than the right-handed one, so if we only included the right-handed factors, the Basic factor would be higher and perhaps even slightly hitter friendly.

That said, the increase likely wouldn’t be high enough to match Fenway. So overall, Turner’s production should increase due to the park switch, though that doesn’t necessarily mean increased fantasy value. Turner should post a higher BABIP and resulting batting average, but see a decline in HR/FB rate, and ultimately home runs. It might end up being a wash for his fantasy value, but perhaps an increase in value in OBP leagues.