Along with its 162-game schedule, lack of a clock, and structure as a series of one-on-one player matchups, baseball's embrace of nonstandardized stadiums sets it apart from the other major American team sports. The dimensions of the outfield and foul territory vary by ballpark, making it difficult to evaluate players' statistics. To determine how good a given player is, we need to separate his performance from the effects of his park.
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. For example, Justin Smoak's (No. 316) first full season in the majors looks disappointing no matter what adjustments you make, but his line appears slightly worse because he spent so much time in spacious Safeco Field. 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 ESPN 500 without any actual change in underlying talent.
Most fans are familiar with the game's more extreme offensive environments -- Coors Field remains a hitter's heaven, Petco Park is where power goes to die -- but there are stories like Smoak's all across baseball. Here are other hitters and pitchers who are probably being underrated or overrated based on how their ballpark affected them in 2011. (Note: Players are listed with their 2011 teams. Some may be on different clubs this season.):