WAR for Pirates prospects

Gorkys Hernandez - mwlguide, Flickr.com
Gorkys Hernandez - mwlguide, Flickr.com
I thought it would be cool to see Wins Above Replacement (WAR) numbers for some of the Pirates’ top prospects. So I started doing some calculating. For offense, I used wRAA from FanGraphs. The only decent measure of minor league defense that I am aware of is TotalZone over at Minor League Splits, developed by Sean Smith of Baseball Projection. Then I simply added positional and replacement adjustments, and added everything up. Take these numbers with a grain of salt, as they are not going to be as accurate as major league stats. First of all, wRAA is not park adjusted. Also, TotalZone does not include batted ball location, as UZR and other advanced metrics do. It is a great tool when we have insufficient data, though (such as in the minor leagues). Finally, other than Jose Tabata, none of these players has reached Triple-A yet. Determining pitcher WAR is kind of a pain, so I chose not to bother. Without further ado, here is estimated 2009 WAR for seven of the Pirates’ top position player prospects. I also computed WAR per 600 plate appearances, to show what each player would have accumulated in an average full season. (Note: I estimated Tony Sanchez’s defense to be about +5 per 150 games, as catcher defense is difficult to measure.)


2009 PA Offense Defense Pos. Rep. WAR WAR/600
Pedro Alvarez 542 31.1 -4.0 2.3 18.1 4.7 5.3
Jose Tabata 402 4.7 -12.0 -2.0 13.4 0.4 0.6
Tony Sanchez 215 16.9 1.8 4.5 7.2 3.0 8.5
Chase D’Arnaud 508 28.9 12.0 5.0 16.9 6.3 7.4
Starling Marte 256 11.3 17.0 -0.6 8.5 3.6 8.5
Robbie Grossman 535 11.7 21.0 -0.3 17.8 5.0 5.6
Gorkys Hernandez 602 -7.4 14.0 2.5 20.1 2.9 2.9


I was disappointed by Tabata’s numbers, particularly his defense. It is clear that he belongs in a corner outfield spot. The rest of the list looks great, though. Marte managed to be worth 17 runs above average on defense, as he and Sanchez each put up MVP-type production in about half a season. D’Arnaud did the same over the entire year. Alvarez and Grossman put up All-Star caliber seasons, while Hernandez’s elite defense allowed him to be a slightly above average player.

Most of these players have a ways to go before reaching Pittsburgh, so it is important to temper expectations. But it is encouraging to see these impressive performances.


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