Defining 'Regular' At Each Position

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At the major league level, teams tell us what they expect from position regulars based on how much playing time they allot to players. That's why we don't present strict league averages by position with this feature. Instead an attempt is made to define position regulars by singling out the most tenured players at each position.

First, we went to Baseball-Reference's wonderful Play Index database. Those players with at least 750 plate appearances (600 PA for catchers) in a two-year span who spend the majority of their time at one position are considered regulars. Left and right field count as one position, corner outfield.

The periods sampled were: 2000-01, when teams averaged 5.01 runs per nine innings; 2005-06, which featured 4.78 R/9; and 2010-11, with its average of 4.37 R/9.

Applying the criteria outlined above tended to exclude those players who were too green or too unproductive or too injury-prone to rack up consistent playing time over the duration of two seasons. It also removed placeholders and injury fill-ins from the sample, while allowing for some disabled-list time by injured regulars.

Also, by setting a high PA threshold, we allow more time for player performance to stabilize. This means that particularly good or bad seasons tend to get evened out, and rookies have time to build steam and hit at a more representative rate.

Using these parameters, we were able to account for between 80 and 90 percent of major league regulars at any one time. The two exceptions being first base and second base in today's game, where teams seem to be in a state of transition as they introduce young regulars.

For example, teams turned over first base last season to youngsters such as Eric Hosmer (Royals), Freddie Freeman (Braves), Paul Goldschmidt (Diamondbacks), Mark Trumbo (Angels) and Mitch Moreland (Rangers). Others like Yonder Alonso (Padres) and Brandon Belt (Giants) and Anthony Rizzo (Cubs) stand on deck for this season.

At second base, Dustin Ackley (Mariners), Jason Kipnis (Indians), Danny Espinosa (Nationals), Jemile Weeks (Athletics), Jose Altuve (Astros) and Darwin Barney (Cubs) all took over in 2011.

With regulars identified around the diamond, we can define average production based on median values at each position. So from each position sample we identify the median value for batting average (which is closely associated with a player's hit tool) and the median value for home runs (hitting for power tool) and then fan out in both directions, using the median as a midpoint.

Think of a player with a median home run total this way: Half the regulars at his position will have more home runs, and half will have fewer. See our position-by-position graphics for a practical application of median values and also to find out which players best exemplify the concept of average for their positions.