Along with its 162-game schedule, lack of a clock, and structure as a series of one-on-one player match-ups, baseball’s embrace of non-standardized surfaces sets it apart from the other major American team sports. Not only are some fields at sea level and others at altitude, some outdoors and others in domes, some made of natural grass and others of turf, but the depth of the outfields, the heights of the walls, and the sizes of foul territory vary by ballpark. These differences aren’t only aesthetic: they also make a significant impact on players’ statistics. To determine how good a given player is, we need to separate his own performance from the effects of his park.

That’s not always easy to do. Some of the players ranked between 301 and 350 on ESPN’s top 500 list have seen their superficial statistics significantly boosted or burdened by their ballparks. Justin Smoak’s first full season in the majors looks disappointing no matter what adjustments you make, but the 316th-place player’s line appears slightly worse because he spent so much time in spacious Safeco Field. It’s extremely hard for right-handed pull hitters to hit home runs in Seattle—as Adrian Beltre discovered before flourishing in more forgiving offensive environments in Boston and Arlington—but Safeco isn’t an easy assignment for slugging southpaws, either.

Without adjusting for Safeco’s effects, Smoak’s True Average (TAv) was a league-average .260. Accounting for the impact of his park—using component park factors tailored to Smoak instead of generic ones applicable to the average left-handed hitter—adds six points to that figure. Had he never left Texas, a launching pad for lefties, his statistics would have seemed more impressive, and he might have placed higher on the list without any actual change in underlying talent.

Elsewhere on the 301-350 portion of the list, Casey Kotchman (304) and Seth Smith (327) can blame (or credit) their ballparks for how their final lines looked, as detailed below. This slice of the list also includes a couple of pitchers who benefited from their ballpark and another who was burned by his. Tim Stauffer (309) and Cory Luebke (333), whose shortcomings were masked by their San Diego surroundings, might not have made it that high had they pitched in other places. Brett Cecil (335), who overcame the obstacle of a home run haven in Toronto, might have stood to move up a few spots in a better pitcher’s park.

Most fans are familiar with the game’s more extreme offensive environments. Coors Field remains a hitter’s heaven, even with the humidor in use. Petco Park is where power goes to die. But those aren’t the only stadiums whose configurations can alter our perceptions of a player. The following hitters and pitchers were hurt or helped most by their ballparks in 2011:

Hitters Helped by Their Parks (Min. 500 PA)

Carlos Gonzalez, Rockies (Unadjusted TAv: .315, Adjusted TAv: .293)
Gonzalez is the poster boy for the Coors Field effect. Over his three seasons in Colorado, Gonzalez has hit .347/.404/.653 at home and posted a pedestrian .271/.325/.452 line on the road, with over two-thirds of his home runs coming in Coors. While Gonzalez’s value might melt away if he ever put on another uniform, he’s not really a mile-high mirage, since most hitters can’t exploit Coors like he can.

Seth Smith, Rockies (Unadjusted: .293, Adjusted: .274)
Smith placed 11 spots below Smoak at number 327 on the top 500 list, but it’s unlikely that he would have ranked so high had he not been hitting in Denver’s thin air. He won’t get the same helping hand from his ballpark this season: PECOTA projects that the pitcher-friendly Oakland Coliseum will lower his TAv by roughly five points, bringing him down to a more pedestrian .273.

Dexter Fowler, Rockies (Unadjusted: .291, Adjusted: .273)
Fowler benefits from a different aspect of the Rockies’ home park than Gonzalez does. Coors’ big outfield makes it the best place in baseball to hit triples, and Fowler’s speed lends itself to exploiting triple opportunities. As a result, he easily leads the majors with 29 triples over the past two seasons.

Josh Hamilton, Rangers (Unadjusted: .312, Adjusted: .297)
The Ballpark in Arlington is the best place in baseball to hit home runs, and lefties receive the biggest boost of all, thanks to the shallow fences in right field and right-center. Sure enough, Hamilton has hit 61 of his 99 home runs as a Ranger at home, which might make teams think twice before making an offer when he hits the free agent market later this year.

Aramis Ramirez, Cubs (Unadjusted: .312, Adjusted: .298)
Ramirez mashed in Wrigley last season to the tune of a .332/.394/.557 line. He hasn’t hit as well in Miller Park, but PECOTA still projects his new home to add six points of TAv to what he’d produce in a neutral park.

Honorable mentions: Alex Avila (Tigers), Troy Tulowitzki (Rockies), Yuniesky Betancourt (Brewers), Adrian Beltre (Rangers), Carlos Pena (Cubs)

Hitters Hurt by Their Parks (Min. 500 PA)

Torii Hunter, Angels (Unadjusted: .271, Adjusted: .285)
In the AL, only Kauffman Stadium is stingier than Angel Stadium when it comes to allowing the long ball, which makes Hunter’s string of four consecutive 20-plus-homer seasons in Anaheim all the more impressive.

Howie Kendrick, Angels (Unadjusted: .274, Adjusted: .290)
Kendrick hit a career-high 18 homers last season, and he probably would have cleared 20 playing almost anywhere else in the league. Singles, doubles, and triples were also hard to come by in the Big A, perhaps the league’s least-recognized pitcher’s park.

Ichiro Suzuki, Mariners (Unadjusted: .234, Adjusted: .247)
Ichiro’s dramatic decline last season wasn’t an illusion, but he didn’t quite sink to the depths that his unadjusted stats might suggest. Even more so than Smoak, he suffered from playing in Safeco.

Jason Bartlett, Padres (Unadjusted: .225, Adjusted: .238)
This list wouldn’t be complete without at least one Padre. Barlett’s bat isn’t an asset anywhere, but Petco made it look even worse than it was.

Casey Kotchman, Rays (Unadjusted: .290, Adjusted: .300)
Kotchman singled in 20.8 percent of his plate appearances last season, the sixth-highest rate in the AL. Considering singles were scarcer in Tropicana Field than in any other ballpark in baseball, his surprisingly successful season may have been even more successful than we thought.

Honorable mentions: Alberto Callaspo (Angels), Mark Trumbo (Angels), Martin Prado (Braves), Matt Holliday (Cardinals), Vernon Wells (Angels)

Pitchers Helped by Their Parks

Aaron Harang, Padres (Unadjusted: .266, Adjusted .291)
The Padres’ plan was simple: put a fly ball pitcher who’d fallen on hard times in Petco Park, then watch those flies die in the outfield. The plan worked to perfection, as Harang recorded his lowest home run rate since 2005 and a career-low ERA. Dodger Stadium suppresses homers almost as much as Petco, so Harang may survive the move to LA mostly intact.

Dustin Moseley, Padres (Unadjusted: .259, Adjusted: .282)
Moseley recorded the third-lowest strikeout rate among NL pitchers with at least 120 IP last season, which made him highly dependent on his park to keep him out of trouble. Fortunately for him, Petco held up its end of the bargain, allowing him to finish with an ERA even lower than Harang’s.

Tim Stauffer, Padres (Unadjusted: .257, Adjusted: .280)
Stauffer isn’t as prone to allowing flies as Harang, but Petco can also aid those who keep the ball on the ground.

Roy Oswalt, Phillies (Unadjusted: .259, Adjusted: .279)
As if teams needed another reason to avoid Oswalt besides his balky back, the 34-year-old’s ballpark may have made him look a bit better than he was. In some circles, Citizens Bank Park retains a reputation as a home run park, but the stats no longer support it: the Phillies’ stadium had the sixth-lowest HR factor in the league last season, which helps explain how Oswalt recorded his best home run rate since 2007. No wonder he’s still looking for work.

Cory Luebke, Padres (Unadjusted: .221, Adjusted: .239)
Luebke is yet another pitcher who called Petco home, but he shouldn’t be lumped in with the veteran reclamation projects at the top of this list. The lefty had the third-highest strikeout rate of any NL pitcher with at least 130 IP, which made him much less dependent on his ballpark to bail him out than any of his fellow Padres pitchers.

Honorable mentions: Kyle Lohse (Cardinals), Madison Bumgarner (Giants), Cliff Lee (Phillies), John Lannan (Nationals), Ryan Vogelsong (Giants)

Pitchers Hurt by Their Parks

Brett Cecil, Blue Jays (Unadjusted: .282, Adjusted: .268)
Rogers Centre had the AL’s third-highest park factor for homers and inflated double and triple rates by roughly the same degree. That makes it a bad place for Cecil—one of the AL’s most fly ball-prone pitchers—to be.

Tim Wakefield, Red Sox (Unadjusted: .288, Adjusted: .274)
Tim Wakefield retired over the winter, but if he’d gone on the Petco plan instead, he might have extended his career even further. Wakefield allowed doubles to 6.6 percent of the batters he faced, the highest rate of any pitcher with at least 120 innings pitched. The park that inflates the rate of doubles allowed more than any other? Fenway.

Brandon Morrow, Blue Jays (Unadjusted: .267, Adjusted: .254)
Morrow’s fly ball rate was just a tick below Cecil’s, but his league-high strikeout rate translates to fewer balls in play.

Alexi Ogando, Rangers (Unadjusted: .239, Adjusted: .259)
The home run park factor that was such good news for Hamilton works the other way for Ogando and the rest of his Ranger rotation-mates. Although Ogando has handled the hitter’s park well thus far, he’d still be better off almost anywhere other than Arlington.  

Freddy Garcia, Yankees (Unadjusted: .272, Adjusted: .252)
Garcia’s career resuscitation was even unlikelier in light of where it occurred: Yankee Stadium was the AL’s second-most-homer-friendly park, and Garcia allowed flies at the highest rate in New York’s rotation. Instead of providing the Bleacher Creatures with a steady supply of souvenirs, he kept his HR rate under one per nine innings. Don’t expect him to sustain that performance this season.

Honorable mentions: Homer Bailey (Reds), Jeff Francis (Royals), Colby Lewis (Rangers), Jason Hammel (Rockies), Bartolo Colon (Yankees)

Thanks to Rob McQuown and Colin Wyers for research assistance.

A version of this story originally appeared on ESPN Insider Insider.

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So, Denver and Arlington good for hitters, San Diego and Seattle bad. Got it.
Curious the Citizen's Bank Park had such a low HR factor last season. Maybe this is a stupid question, because I don't know how park factors are calculated, but could that have anything to do with the Phillies' insanely good starting rotation? i.e., good SPs = fewer homers allowed = makes the park look hard to hit a homerun in.
I've wondered about the same effect on Anaheim. I remember it being called very neutral formerly, but now recently, it's very much a pitcher's park. Coincidentally (or not?), the Angels have assembled one of the league's better rotations in recent years.
Couple that with their offense which has taken a steady decline. I agree.
I'm slightly surprised to see 3 hitters in the top 5 and 1 honorable mention at Coors, yet only 1 honorable mention for pitchers. Is it just that road pitchers suffer more at Coors, or what?