It's rare that a one-week rash of news dramatically shifts our attention to the impact of park factors in fantasy baseball, but here we are.
Between Arizona Diamondbacks general manager Mike Hazen's confirmation on Feb. 13 that Chase Field will have its humidor in working use beginning in 2018, J.D. Martinez's move from Arizona to Boston and Jarrod Dyson's subsequent signing with the Diamondbacks six days later, and the three-team trade involving Steven Souza Jr. and Brandon Drury (among others) the day after that, things were shaken up significantly and park factors became a large part of those conversations.
Change was again at the forefront, as the Diamondbacks' humidor announcement was a potentially huge such change, with significant ramifications. They're the second team to employ a humidor -- a climate-controlled chamber in which baseballs are stored in order to maintain a constant humidity level -- joining the Colorado Rockies, who installed one of their own at Coors Field in 2002.
To give you a sense of what such a change might mean in statistical terms, consider the humidor's impact at Coors: In the five seasons combined that preceded its installation (1997-2001), the venue's park factor for home runs, using the same formula as ESPN's Park Factor page, was 1.566. In the five seasons following its installation (2002-06), Coors' park factor for home runs dropped to 1.291. Its run factor, meanwhile, went from 1.528 from 1997-2001 to 1.301 from 2002-06 -- though bear in mind that steroid testing, which began in 2003, might have had an impact as well.
Whether Chase will endure that kind of dramatic shift -- its five-year park factors (2013-17) were 1.105 for home runs and 1.125 for runs scored -- is the question, and the answer is potentially critical considering the disparity between the parks' pre-humidor factors.
A major difference between Coors and Chase is altitude. Chase might be located at the second-highest altitude (1,061 feet), but that's also 4,119 feet lower in altitude than Coors is. One of the major contrasts between the two is the impact on breaking pitches, as Coors' mile-high altitude reduces the break on pitches, while Chase's altitude doesn't to the same degree. There's a good chance, therefore, that Chase's humidor could have a significantly broader impact on statistics accrued there than Coors' did.
If you're looking for more in-depth analysis on the subject, read Todd Zola's excellent Draft Kit column, which goes into greater detail. Derek Carty has also done great, extensive research on the impact of Chase's humidor, and suggests that it could swing the ballpark to the pitching-friendly side. Both also reference Alan Nathan's column from 2017, when the team first dabbled with the idea of installing a humidor, and Nathan went into exhaustive detail on the topic at the time.
Having compiled and updated the five-year park factors (2013-17) for all 30 venues, as I have for several years now in our Draft Kit, one trend I've noticed with Chase Field is its year-over-year inconsistency in terms of park factors. Of the 27 ballparks that have been open and in operation with the same field measurements for all five seasons, Chase Field was the ninth-least consistent in terms of run scoring, with a runs scored park factor as low as 0.974 (2013) and as high as 1.225 (2016) during that time span. That means that whatever the result of Chase's humidor, we might not even get a true reading on its impact for at least a couple of seasons, and for 2018, its range of outcomes is potentially wide.
Make sure to adjust your projections and rankings accordingly, as we have on our pages, as home runs will almost certainly decline in Phoenix this season, and not simply because Martinez is now a member of the Red Sox. For example, I made two noticeable, key adjustments to my rankings to compensate: Paul Goldschmidt moved from my No. 3 to No. 8 overall player, while Jake Lamb, who generated roughly one-third of his fantasy value in 2017 from his 30 home runs, moved from No. 103 to 133 overall. I'm also more confident in the repeat prospects of Zack Greinke, Robbie Ray and Zack Godley, as well as the profit potential of Patrick Corbin and Taijuan Walker.
Angels lower the fences
Chase Field wasn't the only ballpark to endure a significant change during the offseason. On Feb. 20, the Los Angeles Angels announced that the height of the home run boundary line in right field and right-center at Angel Stadium will be lowered, from 18 feet to eight feet. This was done in order to accommodate the installation of a new out-of-town scoreboard as well as "philosophical changes," per vice president of communications Tim Mead. There will also be new video boards in both left and right field, though both of those sit atop the stands outside of the field of play.
While this might create more excitement for Shohei Ohtani fans, as his left-handed power stroke could obviously benefit, the Angels don't have many specific individuals who should see a significant change in their statistical potential. Yes, Angel Stadium should become more power-friendly for lefty hitters -- it had the 24th-best home run factor (0.884) from 2013-17 -- but the Angels have also hit the fewest home runs to right field of any team in each of the past two seasons (42 in 2017, 27 in 2016).
Kole Calhoun might enjoy enough of a boost to warrant a pick a round or two earlier, though even he comes with questions, having shifted to a more fly ball oriented approach in 2016 that he changed back after a poor first two months of last season. He's the Angels' only regular left-handed hitter, though, and if he shows further shifting to a fly ball approach, he'd become all the more interesting.
Year 1 in the books at SunTrust Park
The Atlanta Braves opened the new SunTrust Park last season, and as suggested might happen in this space a year ago, left-handed hitters experienced a bit of a power boost there, at least when compared to the team's former home, Turner Field. Here is a comparison of the two ballparks, using Turner's five-year park factors from 2012-16 and SunTrust's from 2017 alone:
Turner Field (2012-16): 0.988 run factor, 0.870 home run factor (0.859 for right-handed hitters, 0.882 for left-handed hitters), 1.074 strikeouts factor
SunTrust Park (2017): 0.976 run factor, 0.953 home run factor (0.815 for right-handed hitters, 1.172 for left-handed hitters), 0.988 strikeouts factor
Before you overreact to those numbers, keep in mind that was also written in this space last year that park factors for new venues often need multiple seasons in order to crystallize, so SunTrust's numbers shouldn't be taken as gospel. Still, the decline in terms of strikeouts is another key takeaway, as Turner was previously one of the game's best in that department, whereas SunTrust was merely below-average in it last season. As to why that was the case, anything from altitude -- the Braves play at the majors' third-highest (975 feet) -- to the humidity to the batters' eye to the amount of foul territory to differing hitting approaches, among other factors, could explain it.
That left-handed home run factor, though, continues to make me bullish on Freddie Freeman, who hit .316/.415/.560 in his 54 games there in 2017.
All 30 ballparks' park factors as well as players of note
If you're curious the park factors for specific ballparks from the past five seasons, the full charts are available at column's end, covering runs scored, home runs (including left- and right-handed splits), BABIP (batting average on balls in play), doubles and triples, walks and strikeouts. In addition, outfield dimensions and fence heights, altitude, roof and playing surface data is also listed.
R and HR | BABIP, 2B + 3B, BB, K | Dimensions and details
Here are some key findings within these park factors, focusing primarily on players who changed teams during the offseason:
By going from Arizona's Chase Field to Boston's Fenway Park, J.D. Martinez escaped the potential effect of the humidor, but also went from the eighth-best ballpark for home runs (1.105 factor) to the sixth-worst (0.881). In almost every other respect, however, he moved to the better ballpark, with runs scored - Fenway Park ranked fourth (1.087), Chase Field second (1.125) -- and walks the only two in which Chase had the advantage. After Coors Field, Fenway is the second-best ballpark in baseball for hits and BABIP, thanks in large part to the Green Monster's proximity to home plate. Martinez should make good use of that fence, and the move should bolster his batting average, with the Boston Red Sox's supporting cast pumping up his runs scored and RBIs, even if it costs him a few homers.
Christian Yelich's was one of the winter's most-hyped moves, as his trade to the Milwaukee Brewers sent him from the worst run-scoring ballpark (0.840 factor) to the sixth-best (1.055), and the fourth-worst for home runs (0.848) to the fifth-best (1.179). There's no denying that he enjoyed one of the biggest ballpark upgrades of any individual player, but he's going to need to improve his 60.1 percent career (and 55.8 percent in 2017) ground ball rate in order to capitalize.
Few might be aware of it, but Philadelphia's Citizens Bank Park has been the second-best venue in baseball for home runs the past five seasons (1.258 factor), trailing only New York's Yankee Stadium (1.305). This is something to keep in mind when evaluating matchups for road players, but it's also great news for Carlos Santana, whose power could enjoy a slight improvement with the Philadelphia Phillies.
While Gerrit Cole's move to the American League lands him in the more hitting-friendly league, thanks in large part to the designated hitter, don't make the mistake of assuming his new home, Houston's Minute Maid Park, is a hitters' park. It's only hitting-friendly in terms of home runs (1.053 factor, 11th-highest), but it favors pitchers in every other category, including posting the fourth-best strikeout park factor during the past five seasons (1.072). Cole might not be in anywhere near as bad shape following the league switch as you'd think.
San Diego's Petco Park has now gone five seasons since moving in the fences in right and right-center fields, and during that time it ranked 22nd in home run park factor (0.913), and 22nd for left-handed hitters (0.921), but only 29th in runs scored (0.887). This is still a pitching-friendly environment, but it's not as extreme of one as it was before those outfield distances shrunk. By moving from Kansas City to San Diego, Eric Hosmer chose a home that was actually better for home runs than Kauffman Stadium (0.820, 28th), but worse in every other category except walks.
Toronto's Rogers Centre was strangely pitching-friendly last season, again illustrating the many year-over-year inconsistencies among park factors. It ranked 21st in both runs scored (0.946) and home runs (0.923) last season, but over a five-year span (2013-17), it ranked 11th in runs (1.021) and ninth in home runs (1.091). Randal Grichuk's move from pitching-friendly Busch Stadium to the Rogers Centre could provide him a much-needed boost to his power numbers.
Other announced ballpark changes
Besides the aforementioned changes at Arizona's Chase Field and Los Angeles' Angel Stadium, here is an overview of all other reported ballpark changes since the end of last season, all of which seem more cosmetic in nature:
Wrigley Field, home of the Chicago Cubs: Among other continued renovations, the dugouts have been widened and relocated from 15 to 30 feet down the foul lines, and there will be new club box and field box seats as well as an improved concourse. Read the details here.
Kauffman Stadium, home of the Kansas City Royals: The grass has been replaced for the first time since 1994. Read the details here.
Dodger Stadium, home of the Los Angeles Dodgers: The field-level entrances have been expanded, and landscaping work has added three times as many trees in the outfield as there were previously. Read the details here.
Busch Stadium, home of the St. Louis Cardinals: "Budweiser Terrace," a multi-level common area, will open in the upper right field level, replacing 1,000 seats from six sections. Read the details here.
Safeco Field, home of the Seattle Mariners: The grass has been replaced for the first time since the stadium's opening in 1999. Read the details here.