Eliminating Park Factors: Which Pitchers Will Benefit Most

May 4, 2020

It appears likely that baseball will be played in 2020 but not at normal MLB home stadiums. With park factors becoming obsolete, Nicklaus Gaut examines starting pitchers who would be most helped by moving out of their home parks.

After weeks of half-baked proposals cribbed from rejected "BioDome" scripts, there now seems to be a scrape of light at the end of the no-baseball tunnel. MLB seems to be increasingly confident that a 2020 season will be played, whether it's playing all games in one location (the Arizona plan), playing in multiple warm-weather hubs (Arizona, Florida, Texas), or the newest proposal calling for geographically-aligned divisions.

When baseball returns, hitter paradises like Coors Field, Great American Ballpark, and most of the AL East would likely be gone. The pain of seeing an ace getting chased in Colorado after giving up seven runs in two innings? Gone. A subpar offense going off because the wind is blowing out at Wrigley? Gone. Vince Velasquez giving up eight runs in less than two innings? Go-... Well, at least the weather will be nicer.

Let's look at some of the pitchers who could be helped the most by pitching in more friendly confines than they would've been pre-pandemic.

The Prime Movers

It doesn't take much imagination to realize which pitching staff will be helped the most by avoiding their home stadium. I'll give you a hint: it's 5,200 feet above sea level and once helped power Vinny Castilla to hit 191 home runs between 1995 - 1999.

Obviously, the entire Colorado staff will gain a big advantage from not playing half of their games in the best hitter's paradise baseball has ever seen. Let's save Antonio Senzatela, Kyle Freeland, and 'dem boys for another day, and start with some Colorado prime beef.

German Marquez, Colorado Rockies

198 ADP in NFBC (SP 53)

2019 Stats: 174 IP, 12 W, 175 K, 4.76 ERA, 1.20 WHIP

Marquez finished as SP 21 on the Razzball player-rater in 2018 but the butcher's bill always comes due at Coors. Colorado's latest ace stumbled in his third full season, posting an ERA approaching five and finishing as SP 48. For reference, you generally don't want a top-75 pick to finish the season sandwiched between Marcus Stroman and Anthony DeSclafani.

However, like so many Rockies pitchers before him, Marquez's final line was heavily influenced by his home/away splits:

Those 100 innings on the road don't seem disastrous, at all. In fact, they look eerily familiar. I wonder where we've seen them before?

Oh yeah...All the way back in 2018. It's almost like Marquez was mostly the same pitcher in both seasons but was disproportionally affected by having to pitch half of his games at a thin-aired launching pad. Weird.

A Sea (Level) Change

Coors Field doesn't just affect how far the ball travels, it also affects how pitches move. Take Marquez's four-seamer, which averaged  8.9 inches and 15.2 inches of movement on it's respective horizontal and vertical planes while away from Colorado in 2019.

Then compare that to the 6.1 inches and 11.9 inches that it moved back home and it's easy to see how his command could fluctuate. Inconsistent fastball command is not a prized trait, especially in Colorado where any misplaced pitch might just get parked in Utah.

To visualize these inconsistencies, here are the home and away heatmaps for Marquez's four-seam fastball in 2019:

Let's move to Marquez's biggest weapon, the knuckle curveball. Reconfigured slightly from 2018's version, the hook averaged 84.9 mph in 2019, compared to 82 mph the year before, and almost doubled its movement on both planes. Whether at home or on the road, the usage stayed steady and continues to be Marquez's premier put-away pitch, being thrown 50% of the time in two-strike counts, with a nearly 24% swinging-strike rate overall.

But it was the same old story at home, with the horizontal movement decreasing from 3.7 inches to 2.7 inches and the vertical drop going from 3.8 inches to 3.4 inches. These are seemingly slight differences but again the heatmaps tell a story of inconsistent stuff:

All the evidence seems to point to the biggest difference between Marquez in 2018 and 2019 was that he got "Coors-ed" in the latter, and a little Rocky Mountain lucky in the former. It's not hard to look at Marquez's 2019 splits and wonder what a de facto "road-only" season could look like. Do you want to know how many pitchers in 2019 had less than a 3.80 ERA and 1.10 WHIP, with a 24% K-rate, or better? Just 12 and you could probably guess all of them besides Sonny Gray.

I already thought Marquez was a great buy for the price and I'm not sure anyone could be helped more by the proposed changes. Even if pitches moved the same at Colorado as they do elsewhere, Marquez would see a huge bump in value just from hitters not occasionally being able to bunt a ball over the centerfield fence. But in addition to this obvious benefit, the bigger jump may come from his ability to finally trust that his stuff will act consistently from game to game.

It's almost cheating to pick a Colorado pitcher so let's go around and find a few more pitchers who'd be better off if they were able to avoid their home ballpark all season.

Mike Soroka, Atlanta Braves

105 ADP (SP 28)

2019 Stats: 174.2 IP, 12 W, 142 K, 2.68 ERA, 1.11 WHIP

He finished as SP 20 on the Razzball player rater in 2019 but I've never been in on Soroka repeating the performance. My issue is that most of his value was earned by a sparkling 2.68 ERA, with 42% of his $13.6 in earnings coming from the category. How do his 2019 ERA evaluators feel about a 2020 repeat?

While not perfectly predictable, xFIP and SIERA tend to be fairly sticky when it comes to estimating a pitcher's ERA in the following season. In a vacuum (and in a normal season) I'd be counting on something closer to a 3.68 ERA than a 2.68 ERA. Pitchers can certainly earn value with such a mark but rarely without big strikeout numbers.

The Braves rookie only struck out 142 batters in nearly 175 IP, finishing with a paltry 20.3% K-rate. Soroka has a four-pitch mix, relying on his two-seamer around 44% of the time, followed by a slider (24.3%), four-seam (18.7%), and changeup (12.4%). His two-seamer is a groundball machine - with a 63.7% GB% - but will never be confused for a strikeout pitch. And his slider had just a 16.5% SwStr%, good for 53rd among starting pitchers who threw at least 100 pitches.

There might be some hope for Soroka's whiffery with his changeup, a pitch thrown just 12% of the time overall, and only 14% in two-strike counts. It was lightly used but the pitch did have a 22.1% SwStr% that was the fifth-highest among starting pitchers, sandwiched between Stephen Strasburg and Lucas Giolito. Batters also had a lot of trouble squaring up the pitch, posting a .221 wOBAcon, .267 xwOBAcon, 4.9% Brl%, and 77% weak-contact rate that were all the high marks in his arsenal.

Out of the (Sun) Truist and Into the Shade

Home field was no advantage for Soroka, with the rookie posting a big disparity of results at what is now Truist Park - especially when it came to his fantasy calling card.

So, not great. The former Suntrust Park is all kinds of kindly to the wrong-handed batters and Soroka already struggles against them. Going by Baseball Prospectus park factors, Atlanta's 105 PF for overall runs was the sixth-highest for left-handed batters in 2019 with the hot summers of Atlanta certainly not helping keep the ball in the park. As for Soroka's batter splits?

Connecting the dots is easy; Soroka struggles everywhere against lefties and pitches in a home ballpark that's very conducive to left-handed hitting. If you take a bad pitcher versus lefties out of a park where lefties tend to crush, you'll probably have more success.

For me, however, it'll still be a hard pass due to his combination of a near top-100 draft price, limited strikeout potential, and current inability to get left-handed batters out. Now, if MLB puts forth a reopening proposal that includes right-handed pitchers not being allowed to face left-handers*, then I'm all in.

*Somewhere, Carlos Martinez just shed a single tear in recognition of how happy he is to even hear such a thing. 

Lightning Round

Gerrit Cole, New York Yankees

You would think that it would be impossible for Cole to go under the radar after signing for $324 million but spending 2020 anywhere besides his new home in New York would likely be a larger boon than people realize. For one, he wouldn't be playing half of his games in the bandbox that Steinbrenner built. Cole doesn't have any troublesome splits but it can't be ignored that Yankee Stadium is consistently a hitter's haven for left-handers.

It also can't be ignored that his new division has three very hitter-friendly stadiums in Boston, Toronto, and Baltimore. Between those divisional matchups and home games, that's 107 Yankee games that would've taken place at some of the softest hitting parks in baseball.

Going into 2020 I never had many reservations about Cole taking a step back in skill, but just like Coors, the AL East meat-grinder will get its pound of flesh. Everyone who took the risk of taking Cole early has to be dancing for joy.

Lucas Giolito, Chicago White Sox

Another ace that could get ace-ier if he gets to play outside his home stadium on the South Side. The former top-prospect broke out for real in 2019, with a 3.41 ERA and 32.3% K-rate over 176.2 IP. But Guaranteed Rate field is a guaranteed boost for batters, particularly when it comes to left-handed dongs, boasting the number-one home run factor for lefties.

The right-handed Giolito actually got hit harder by righties in 2019, with a .306 wOBA versus a .241 wOBA, but still gave up 1.11 HR/9 to left-handers. Giolito would not only be moving to a friendlier environment but now has one of the best framing catchers in baseball behind the plate (Yasmani Grandal, 17.0 FRM) after having one of the worst (James McCann, -9.0 FRM) in 2019.

More 2020 Fantasy Baseball Advice