Lucas Giolito Becomes an Angel

Last Wednesday, the Angels acquired starting pitcher Lucas Giolito in a rare week-before-the-deadline splash trade. The 28-year-old broke out in 2019 to finally make good on his former top prospect status, and has been excellent ever since, save for last year’s disappointing results. He has spent the majority of his career with the White Sox, calling Guaranteed Rate Field (GRF, or whatever company paid up for naming rights each year) his home, but will now be heading to a new home park, the more simply named Angel Stadium (AS). How might the change in home park affects his results? Let’s consult the park factors and find out.

Well this is a fun comparison! Unlike my last two that were sweeps or nearly sweeps, there’s an interesting mix of “winners” here.

Let’s start out with the hit type factors. Both parks suppress every non-home run hit type, which is interesting to see. AS is slightly less pitcher friendly than GRF is, but the difference is small enough that defensive support and luck are going to end up playing larger roles. The Angels’ pitching staff ranks 17th in BABIP, while the White Sox sit 14th, at just .001 apart. Meanwhile, the Angels rank 13th in UZR/150, while the White Sox rank 20th, but the gap widens when looking at the Def metric, where the Angels rank 10th and White Sox sit dead last. This suggests that the Angels are trotting out a better defensive unit than the White Sox, but since Giolito’s .279 BABIP is already well below the starting pitcher league average of .296, I don’t think there’s a whole lot of room for him to benefit from even better defense.

AS has also suppressed doubles ever so slightly versus a more pitcher friendly environment for those hit types at GRF, while the gap widens when looking at the triples factors. It’s pretty clear that while both parks seemingly reduce BABIP, GRF does so better, and sure enough, Giolito has posted a .266 career BABIP at home, but a .290 mark away. That’s a big difference that is likely to be explained at least partly by his home park, as opposed to the standard home field advantage. We’ll see if the Angels defensive improvement can offset the park difference here.

Moving along to the home run factors, we find two parks that dramatically inflate the long ball. Last year, AS ranked in a tie for fourth highest HR factor, while GRF ranked third. Luck is going to have a much larger impact here over the rest of the season than the change in park and ever so slight less hitter friendly factor in Anaheim. Giolito’s HR/FB rate has remained amazingly consistent from year to year, tightly ranging between 13.3% and 14.4% since 2018. His home park definitely deserves some of the blame, as his 15.2% HR/FB rate there is meaningfully higher than his 13.4% mark on the road. It’s too bad his new home park won’t play much better.

Next are up the plate discipline metrics, where the two parks are as similar as it gets, without being equal. Here, we find AS increasing strikeouts slightly versus a neutral factor at GRF, while walks are increased a bit more at AS, versus only slightly at GRF. Giolito hasn’t been able to get his strikeout rate back above 30% like he posted during his 2019 breakout and short 2020 follow-up. The park switch alone is unlikely to change that.

Let’s jump over to the batted ball type factors that matter next. While not highlighted because there’s no “good” or “bad” FB factor, it’s interesting to note that GRF meaningfully increased fly balls last year. Giolito is a fly ball pitcher, and he’s posted a higher FB% at home than on the road throughout his career. So the shape of his batted ball profile could potentially change. The line drive and infield pop-up factors do matter and both favor GRF. These factors will influence the hit type factors, so it’s not really correct to believe this gap will have an additional negative impact on Giolito’s BABIP, as the differences here likely already factor into AS being less pitcher friendly in the hit type factors.

That said, Giolito has had trouble giving up line drives the last couple of years, but has posted the second lowest mark of his career so far this year. Meanwhile, his IFFB is also the second highest of his career. It’s possible he allows more liners and induces fewer pop-ups in his new park, which could raise his BABIP…unless the better defense could convert these batted balls into outs! See, there’s lots of moving parts here, so it’s always difficult to definitively state how a player’s stats will be affected by a team move.

Finally, we end with the run scoring summary stats, FIP and Basic. Both parks played as hitter friendly, but it’s weird to see AS with a lower FIP factor, but higher Basic factor. Whatever the explanation is, it’s pretty clear that the park switch shouldn’t have much, if any, impact on Giolito’s results. The seemingly better Angels defense is a positive, but with all their injuries, their season defensive metrics aren’t very helpful in assessing their current fielding ability. The Angels have also trotted out a significantly better offense than the White Sox, but with nearly their entire starting lineup currently on the IL, this current group isn’t nearly as good. That said, they would have to be far worse to match the White Sox’s futility, as they rank just 27th in wOBA on the year.

I’d say this trade is a very slight positive for Giolito’s fantasy value, but shouldn’t be significant enough to celebrate as an owner or target him in a trade now because you expect far better results.