Park factors (like all stats) are not perfect and especially tricky because they require an extra-long sample before we can take any of the information too seriously. At the same time, they can be crucially important when valuing fantasy players.
I was only halfway joking when I attributed Christian Yelich winning the MVP last season based solely on switching from a home pitcher’s park to a hitter’s one. It’s a unique aspect to baseball, having no park or field be the same.
This is by no means an exhaustive look (and the reason as to why these parks play the way they do is another discussion altogether), but let’s examine the results over the last three seasons from some of the bigger outliers (top-five or bottom-five in MLB) in the most important areas to fantasy players — homers (with splits) and runs scored.
All information comes from “The Bill James Handbook,” and for reference, the average index is 100. So if a team has a park index of 120, that means it was 20 percent greater than league average.
RIGHTY POWER (Top-five in increasing Home Runs for RHB)
Phillies (Citizens Bank Park 124)
Yankees (Yankee Stadium 122)
Rockies (Coors Field 122)
Reds (Great American Ballpark 117)
Orioles (Oriole Park at Camden Yards 115)
J.T. Realmuto goes from a home park that was last in the league at boosting homers (see Marlins below) for RHB to one that has increased them the most over the last three seasons. He stopped running last year, but he should set a career-high in HRs by a wide margin in 2019 … Andrew McCutchen gets a near identical boost moving to Philly from San Francisco, and he’s one of the best outfield targets in drafts right now, with his ADP way underpriced. His HR/FB% dropped nearly in half at AT&T Park last season.
DJ LeMahieu makes a lateral move from Colorado to New York, at least in the power department, while it’s another reminder to go draft Gary Sanchez … Yasiel Puig goes from a tough park for power for righties (Dodger Stadium 93) to one of the most favorable in baseball, and GAB also ranks top-five in the N.L. in increasing run scoring (and among the league-leaders in boosting walks). Nick Senzel will find himself in a great spot as soon as the Reds give him a chance … Pitching in Baltimore does no favors to Dylan Bundy, who finished with the sixth-highest FB% last season.
(And the bottom-five)
Marlins (Marlins Park 73)
Giants (AT&T Park 74)
Pirates (PNC Park 74)
Cardinals (Busch Stadium 81)
Braves (SunTrust Park 84) *2017-2018 only
The Marlins’ combination of having an extreme pitcher’s park and little talent makes them the heavy favorite to score the fewest runs in baseball this season, although LHP Caleb Smith is a fantasy sleeper. Marlins Park also bumps up K rate, which doesn’t seem like an ideal fit for new starting right fielder Peter O’Brien, whom THE BAT projects for a comical 40.3 K% … Any added run support or improved defense would likely be more than offset by Madison Bumgarner and his fading fastball leaving San Francisco’s climate, so fantasy owners should strongly hope he’s not traded (and he likely will be).
Keone Kela saw a hugely improved situation when he was traded from Texas to Pittsburgh last year, while Paul Goldschmidt will be in a tough hitting environment for the first time in his career (although thanks in part to the humidor he struggled in Arizona last year, posting a .782 OPS compared to 1.053 on the road) … The very early returns on SunTrust Park suggest it increases run scoring (tied for 11th) while decreasing homers (sixth-fewest) over its first two seasons.
LEFTY POWER (Top-five in increasing Home Runs for LHB)
Yankees (Yankee Stadium 138)
Angels (Angel Stadium of Anaheim 134) *2018 only
Phillies (Citizens Bank Park 125)
Reds (Great American Ballpark 124)
Brewers (Miller Park 124)
It must be emphasized that just one season of park data needs to be taken with a grain of salt, but last year’s lowering of the outfield wall in Anaheim had a major impact. Justin Bour is a sleeper to hit 30 homers, while Shohei Ohtani could be a difference maker once he returns to DH.
Switch-hitter Aaron Hicks benefits from both sides at the plate in Yankee Stadium, while Citizens Bank Park and GAB also appear on both the righty and lefty HR leaderboards, so new Reds starters Alex Wood, Sonny Gray and Tanner Roark receive downgrades. It’s a much more drastic change for Wood than Gray, and it’s extra concerning for Roark, who saw his GB% drop nearly eight points to a career low last season.
Yelich owners are fans of Miller Park, which was a terrific landing spot for Mike Moustakas’ fantasy value. He didn’t take advantage of it in a limited 91 at-bats last season in Milwaukee, but Moustakas goes from hitting in arguably the roughest park for lefty power (see Kauffman Stadium below) this side of AT&T during his entire career, to one of the more favorable venues. Miller Park also boosts run scoring (102) in general, also making Travis Shaw and his 2B eligibility an enticing target.
(And the bottom-five)
Giants (AT&T Park 60)
Royals (Kauffman Stadium 78)
Red Sox (Fenway Park 79)
Padres (Petco Park 81)
Cubs (Wrigley Field 82)
When San Francisco built AT&T Park, it appeared it was being tailor-made for left-handed (and Barry Bonds’) power, with short dimensions in right field. But thanks largely to climate and unforeseen circumstances, it’s simply been the toughest place to ever hit home runs from the left side of the plate, certainly over the past 30 or so years. Not that we needed another reason to consider Bonds the greatest hitter of all time, am I right? It’s too bad Brandon Belt doesn’t hit elsewhere (or stay healthy).
Fenway Park is unequivocally a hitter’s park, but its quirky dimensions in right and The Green Monster in left lead to a venue that ranks top-three in boosting run scoring yet bottom-three in lefty power. Fenway and Coors Field are the two parks that create far and away more doubles than any other. Both benefit from hitting in Fenway Park, but J.D. Martinez does a lot more so than Rafael Devers.
Jake Junis had an inflated HR/FB% (18.6) at home last season that looks especially unlucky given this context, so he’s a strong SP target later in drafts … Eric Hosmer hasn’t had it easy during his career in KC and SD, while the Cubs’ current approach of being lefty-heavy both in their lineup and rotation doesn’t appear a good fit with their home park.
RUNS SCORED (Top-five leaders in increasing runs scored)
Rockies (Coors Field 133)
Rangers (Rangers Ballpark in Arlington 124)
Red Sox (Fenway Park 110)
Indians (Progressive Field 110)
Yankees/Twins/Diamondbacks 106) *Chase Field 2018 only
Daniel Murphy gets the obvious big boost moving to Colorado (it just missed the above lefty power list), although Nationals Park (105) would rank next here in runs scored, so he was already in a nice hitting environment. German Marquez is an underdog to finish with a sub-4.00 ERA given his tough environment.
Asdrubal Cabrera is an afterthought in most fantasy drafts, but he goes from hitting in one park (for the majority of the last three seasons) in Citi Field that ranks second-worst in run scoring to one that’s been second-best in Texas. He’s a sleeper who offers nice flexibility while eligible at 2B/SS/3B … Fenway Park has increased batting average by eight percent over the last three years, which is the third-most in MLB.
Corey Kluber (and the rest of the current Cleveland staff) deserves extra credit for dominating while in the A.L. and also throwing in such a hitter’s park, while Target Field may fly a bit under the radar as one.
And now we get to the humidor effect. From 2015-2017, Chase Field ranked third in run scoring, with an index of 117. In 2018 after the humidor was introduced, it fell to sixth (106). The home run index in Chase Field last season (94) dropped to 19th in the league, so the expected changes in reduced exit velocity and/or an improved pitcher’s grip certainly had an affect on cutting home run rates.
It’s been just one year, and there’s no doubt noise (baseballs in general seemed to change from 2017 to 2018, and there has to be more of an explanation for Goldschmidt’s wRC+ dropping from 180 on the road to 108 at Chase Field last year), but early returns suggest the humidor makes Chase Field a less favorable hitter’s park (but still one), with the biggest impact being a noticeable drop in homers.
(And the bottom-five)
Marlins (Marlins Park 81)
Mets (Citi Field 85)
Dodgers (Dodger Stadium 88)
Astros (Minute Maid Park 89) *2017-2018 only
Mariners (Safeco Field 90)
It’s too bad Miami doesn’t have more hurlers to take advantage of in what’s been the most extreme pitcher’s park over the last three seasons, although I imagine the opposite could be said about its hitters (none are good enough to get upset over them losing any value).
Newcomers Wilson Ramos, Robinson Cano, Jed Lowrie and Keon Broxton all join a decidedly pitcher’s park in New York, while James Paxton sees a dramatic change in venues going from Seattle to Yankee Stadium. Noted pitcher’s parks AT&T (95), Petco (96) and Tropicana Field (92) all just missed my arbitrary cutoff point here, as they still remain places to target pitchers over hitters.
Lastly, there’s Minute Maid Park in Houston, which has seen a big change after the removal of Tal’s Hill in centerfield before 2016. During each of the last two seasons since, Minute Maid Park has ranked last according to Fangraphs’ runs scored park factors, so it’s quickly become an extreme pitcher’s paradise despite the short porch in left field.