Red Sox Position Adjusted Batting Stats

Mike Rodgers of Tigers By The Numbers had a neat post running over at Bless You Boys yesterday. In it, he took a look at the position adjusted batting statistics of the Detroit Tigers. Of course, this immediately had me wondering where the Sox players graded out under the same criteria, so to Excel I went!

Before we get to the numbers though, let’s lay some framework. First, what’s the benefit of using position adjusted metrics? Well, they offer a direct comparison to a player’s closest peers. As Mike observes, while shortstop Jhonny Peralta‘s has notched a 98 wRC+ this season, two percentage points worse than the league average hitter (100), he’s actually been 16 percent better than the average American League shortstop. More often than not, isn’t the latter what we really care about? Convenient as it is to put all batters on the same scale, they aren’t all capable of fielding the same position.

The first step in computing position adjusted statistics is to identity their averages. We can (and Mike did. Thanks Mike!) calculate the league average wOBA by position using Baseball Prospectus’ league batting by position page and for the weighted run values, Fangraph’s GUTS section. In these averages, Mike identified a few seasonal trends. The most interesting to me was that production out of center field, historically a low-offense position, has been greater than all other positions except first base and designated hitter.

With the positional average wOBA’s in hand, we can use the wOBA’s of each Sox player to calculate both the offensive runs each player has contributed above average (wRAA) as well as their wRC+, both relative to their position. To cut down on the leg work a little bit, I’ve limited the following table to position players with at least 100 plate appearances. One drawback of the following chart is that it is not park adjusted. Historically, Fenway is a high run environment, so Sox batters may have received an “unfair” boost. Adjusting for park wouldn’t flip the results upside down (we’re looking at less than a season of games, only half of which have been played at home, leaving less time for park factors to bare out), but it’s worth keeping in mind.

A couple of interesting things jump out.

Dustin Pedroia‘s production at the plate has been off. His .282 batting average is well below his career mark (.302) and his OPS is some 50 points off the norm. Even in his worst offensive season since his rookie year though, he’s still significantly better than most second basemen. His 16.2 runs above average by position are second on the team and translate to about a win and a half (ten runs equate to one win).

A little further down the list we come to Pedro Ciriaco. That Ciriaco, in just 144 plate appearances, finds himself squeezed between Cody Ross (397 PAs) and Will Middlebrooks (286 PAs) is a testament to two things. For one, the run environment at shortstop is well below that of left field and third base, but secondly, Ciriaco has really raked this year. While it’s not wise to expect him to keep at this pace, it’s been a fun ride. On a rate basis, Ciriaco’s run production relative to the position is the team’s highest (165 wRC+), even above David Ortiz (159 wRC+)!

While I’m ready to turn the page on the negatives of this season, I have to point out the woeful production of the recently traded Adrian Gonzalez, as well as Red Sox center fielders. While playing at second base provides Dustin Pedroia a low floor to build upon, the same cannot be said for Gonzalez and first base. Gonzalez’s .300/.343/.469 triple-slash line with the Sox fell well below his career average (.294/.372/.509) and provided the team with just a six percent bump over the average American League first baseman. In center field, Jacoby Ellsbury and Marlon Byrd have combined for a dismal 8.9 runs below average, nearly a full win, or in this case, loss.