The Effects of Chase Field’s Humidor

(Norm Hall/Getty Images)

Let’s enter the conspiracy zone.

From 2009-2016, the Arizona Diamondbacks never had a team ERA within the top 13 of the MLB. Entering the 2017 season, the Diamondbacks hired Mike Hazen as their new GM. During the 2017 season rumors began to swirl that the D-Backs may introduce a humidor for the second half of the season. As the pitching staff shockingly performed to the tune of a 3.66 ERA, the 3rd best in the MLB, the Diamondbacks offense banked on power from Jake Lamb, Paul Goldschmidt, and mid season addition JD Martinez. Conveniently, the Diamondbacks humidor wasn’t ready in time for the 2nd half of the 2017 season.

As the D-Backs offseason began, they owned a roster where all 5 starting pitchers return. As JD Martinez locked in with Boston, the Diamondbacks added speedster Jarrod Dyson and dual threat power/speed Steven Souza. As glove first Nick Ahmed is expected to start at shortstop, Mike Hazen has put his final touches on his humidor savvy roster. With an emphasis on defense and pitching with up to 6 players in the daily lineup capable of double digit steals, the humidor (and the D-Backs roster) is ready.

While the real life Diamondbacks are poised for great things with the humidor, the same can’t be said for the D-Backs offense from a fantasy perspective. The effects a humidor could have on Chase Field is wide varying. For example, Coors Fields averaged 3.20 homers a game through 7 humidor free seasons. After the humidor was installed, the home run rate at Coors Field dropped to 2.39 homers a game (2002-2010), a 25% drop. Alan Nathan, a physics professor at the University of Illinois, predicted that there could be 25-50% drop in home runs at Chase Field due to the dry Arizona air versus Colorado’s air.


Paul Goldschmidt is an elite hitter, no question about it. In the final humidor free Coors Field season in 2001, the Rockies had 2 elite hitters in Todd Helton and Larry Walker. Here are their 2001 humidor free season versus their 2002 humidor debut season.


As Todd Helton’s 2001 humidor free 49 homers were a career high, Paul Goldschmidt tied a career high in 2017 with 36 homers, 20 of which came at home. Walker and Helton combined for a near 25% drop in home homers with the humidor. Paul Goldschmidt has 89 career road homers and 87 Chase Field homers. While his home/run power splits are even, Goldy has hit more than 15 homers at Chase Field twice. Natural power regression could come for Goldy like it did for Helton, which further dampens Goldy’s power outlook. I believe Goldschmidt is a lock for 25 homers in 2018, but I’d take the under on a 30 home run season.

Before you dump all your shares of Paul Goldschmidt, do not ignore his speed. Goldy stole 19 bases last season, but only 5 of which came after they acquired JD Martinez. With Martinez gone and the D-Backs looking to be aggressive on the base paths, Goldy does have 25/25 potential which solidifies him as a first round pick.

AJ Pollock, the D-Backs 2nd biggest offensive fantasy player, had his series of question marks even before the humidor was announced. In 6 seasons, AJ Pollock has played over 75 games just 3 times and has missed 25 or more games in all but one season. Pollock’s value comes from his 162 game average of 16 homers, 28 stolen bases and 286/343/464 slash line. AJ Pollock’s one fully healthy, injury free season produced 315/367/498 slash line with 20 homers and 39 stolen bases. Entering his age 30 season, as of me typing this he is fully healthy. Pollock’s value comes with his speed and I think the humidor is least of his worries.

While Goldschmidt and Pollock still have promising outlooks with the humidor effect, the same cannot be said for Jake Lamb. Simply, the humidor is coming for Jake Lamb’s value.

In the last 2 seasons Jake Lamb has averaged a 248 AVG, 29.5 HR, 6 SB, 98 RBI. 35 of Jake Lamb’s 59 homers have come at Chase Field. It is very realistic that Jake Lamb could see a 5-6 homer drop which turns Lamb into a 25 homer max player at a deep 3B position with little to no speed and poor average numbers. As someone who is virtually unusable versus LHP (.144 AVG in 2017), Lamb has his flaws. As Paul Goldschmidt loses maybe 2-3 spots in the first round, AJ Pollock is already subject to how much risk you want in the 50-70 range, Jake Lamb drops from an emerging top 100 pick to 126 according to NFBC (National Fantasy Baseball Championships) in the last 6 weeks. Lamb dropped to pick 140 in the most recent draft I’ve done.

For the rest of the Diamondbacks hitters, the humidor lowers their value, but not significantly. Steven Souza doesn’t have a Chase Field track record but he should produce a solid HR/SB mix (30 HR, 16 SB in 2017) at pick 184 via NFBC as long as its an OBP league. Fellow OFer David Peralta should be able to maintain a .290 average and .350+ OBP but his limited power (18 homers in last 760 PA’s) is worrisome considering he has just 7 road homers in that span. Jarrod Dyson is a one tool stolen base dart throw at the end of drafts and just forget Yasmany Tomas exists.

The Diamondbacks middle infield options face the same fears David Peralta has. Chris Owings is going at 231 currently and offers position flexibility at 2B, SS, OF and 20 SB potential. Unfortunately, a 9 homer, 257/295/390 162 game average slash line isn’t too promising. As Nick Ahmed is essentially a glove only player, Ketel Marte is the middle infielder to own at his 339 ADP price tag.  Marte will have 2B/SS elgibility and offers the slightly better average and power numbers (260/345/395 2017 line) when compared to Owings while being 2 years younger and more locked into a starting role. Marte stole over 20 bases in a season twice in the minors.

Unless you’re in a 15 team, 2 catcher league, don’t even think about owning Jeff Mathis or Alex Avila. The two should see a near even split in playing time with the potential of the Diamondbacks using a 3rd catcher at times as they did all of 2017.

The humidor effect is real, but will effect some more than others. Rule of thumb should be this, home stats should see around 25-33% drop in homers with a 10-15 point dip in averages, so plan accordingly.

The good news for fantasy players is the positive effect the humidor will have for Diamondbacks pitching. As the Diamondbacks commit to having a strong pitch framing catching group, their overall defense continues to improve. Like I pointed out earlier, Jarrod Dyson and Steven Souza are plus defenders. Nick Ahmed is an elite defensive shortstop and Ketel Marte seeing a large amount of time at second base further improves the defense. All of which is great news for Diamondbacks pitching.

As Robbie Ray and Zack Greinke locked into top 15 SP options even before the humidor news, the rest of the starting rotation offered fantasy value too. Zack Godley is a real SP3 and Taijuan Walker and Patrick Corbin are intriguing SP4’s. With the humidor now at Chase Field, the D-Backs starting rotation hype train has left the building. Here are the 2017 home/road splits for the D-Backs starting rotation members.


The top 4 members of the Diamondbacks rotation had strong away ERA’s. While the humidor should comfortably sit the Zack’s in the low 3’s ERA range, Taijuan Walker and Robbie Ray could be massive humidor winners. Robbie Ray could seek legit top 10 SP potential, Taijuan Walker could make a SP3 bid. As for Patrick Corbin, that is a difficult case to solve. Corbin’s been historically good at Chase Field as his 2013 All-Star season featured a 2.97 ERA at home and 3.90 ERA on the road.

The Diamondbacks starting pitching ADP’s still present intriguing value. Zack Greinke at pick 47 is fair value, but Robbie Ray at pick 48 is a steal. Zack Godley’s ADP is 124, going right behind Jon Lester. Taijuan Walker’s ADP of 209 is another awesome price later in the draft and Patrick Corbin is going 233.

In short, the humidor is obviously great for Diamondbacks pitching and bad for Diamondbacks hitting. It is a very real factor that cannot be ignored on draft day. Use it to your advantage.


By Todd Williams

For more Todd Williams content follow him on Twitter @GoldyHappens and subscribe to the Fantasy Front Office Podcast











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