Derek Shelton: The 2011 Rays Offense Vs. Projections

Attempting to quantify the value or effect of a hitting coach is generally deemed worthless, if not dangerous. Yet, the notion of ignoring what is difficult to measure seems to be even more reckless. Stats like batting average do have meaning, they just pale in comparison to other metrics that make a greater attempt to neutralize for park, luck and other factors which can make true talent levels difficult to estimate. Catcher defense was seemingly ignored forever because of measurement difficulties. Now, many pundits express with great confidence that Jose Molina's glove is worth an additional two wins for the Rays.

Measuring a team's offense against other teams in the league by any non-park-adjusted metric has obvious flaws. However, we can take a player's performance and retroactively compare it to his pre-season projection to gain an idea of whether or not he exceeded expectations. Below is a table of the 2011 Rays' Zip Projections for wOBA and their actual performance, along with the amount the performance over or under performed their projections. Given the definition of projections, it would be normal to expect an even distribution of over and under performers.

Twelve of the sixteen players with a minimum of 90 plate appearances failed to meet their pre-season projection. However, there is a flaw in the average being a shortfall .024 of wOBA. Dan Johnson's 91 plate appearance under-performance should not be counted equally with Casey Kotchman's over-performance in 563 plate appearances. If we weight the Deltas by the number of plate appearances the difference is a more palatable -.007. This, too, has a bias to be aware of in that your biggest letdowns are severely under-weighted while the top surprises carry substantial weight. To gain some perspective, we can measure the weighted Deltas across the American League East.

Even with the Summer of Kotch the Rays greatly underperformed expectations. A similar exercise (The Derek Shelton Effect) in 2010 also produced dismal results. I won't ever claim to be a swing mechanic, but the evidence that the Rays sharply underperformed projections in both seasons during the Derek Shelton era gives me great pause.