Fantasy baseball owners who compete in auctions are wise to keep a guide handy. Keeping track of the values of 200-300 ballplayers is a tough challenge. Fortunately, many of the top fantasy baseball service providers offer their users nice tables for reference purposes.

Of course, the guides aren’t perfect and we’ve reviewed the top 20 reasons why fantasy baseball auction guides may not accurately forecast the results of your auction.

ESPN has some very smart fantasy baseball analysts and publishes a good auction guide. We appreciate how the website lets you sort values by position. But they also base their values on 10-team leagues whereas many of those who play fantasy baseball participate in 12-team leagues or more. Combined with a bit of a general auction guide bias towards even spreads among player values, the end result is often undervaluing of top superstars, undercounting of $1 or $2 players, and overemphasis on mid-value players in the $6 to $12 range.

Here’s a block histogram (java required) that visualizes ESPN’s projected auction values in 2009.

Now, let’s take a look back to 2008 to see the results of average auction price in a 12-team league. The results have been rounded to the nearest dollar. Pay attention to the number of players sold for more than $30 and the number of players who were bought for $3 or less. The histogram below also serves as a useful reminder on player values heading into the 2008 season.