The most obvious thing to note: elite prospects are super valuable for a reason. The best hitting prospects from 1994-2005 averaged +16 WAR during their team controlled years, and the best pitching prospects weren’t even that far behind, at +13 WAR over the same period; the #11-#25 hitting prospects almost matched that total as well. A top 25 hitting prospect or a top 10 pitching prospect regularly produced high levels of performance in their pre-arb and arbitration years.
And as much as everyone likes to bag on prospects for being unproven, the bust rates of these types of players was actually quite low; only about 1 in 10 produced nothing at the big league level. At the very top of the prospect charts, Baseball American did an excellent job of identifying players who could make an impact at the big league level, and the risk associated with these kinds of players is generally overstated. Elite prospects often turn into good big leaguers, and the rarely turn into nothing.
As a point of comparison, I looked at the leaderboard for the best under-32 pitchers from 2006-2008, to see how well they would perform in the six seasons from 2009-2014. The 10 best not-old pitchers in that three year window: Roy Halladay, Johan Santana, CC Sabathia, Dan Haren, Jake Peavy, Roy Oswalt, John Lackey, Brandon Webb, and then either Javier Vazquez and Josh Beckett if you’re using FIP based WAR or Cole Hamels and Carlos Zambrano if you’re using RA9 based WAR.
During this three year span, these aces averaged roughly +15 WAR, making them established five win pitchers with a significant track record of success. The age limit helps keep the list to just pitchers who reasonably should have been expected to have six years left in their big league careers. How’d they do over these past six seasons?
Halladay, Sabathia, and Hamels were awesome, producing at least +20 WAR by either FIP or RA9 versions of WAR. Haren was close, getting +20 WAR by FIP and +17 by RA9, and he threw the most innings of anyone in the group as well. But after those four, it’s a pretty big mixed bag, with some good performances, some bad performances, and a lot of injuries. Brandon Webb basically never pitched again. Carlos Zambrano and Johan Santana were okay when they were healthy, but weren’t healthy much. Oswalt had some good seasons and some bad seasons; ditto John Lackey.
All told, the top 10 pitchers by 2006-2008 FIP-WAR produced +14 WAR/+13 RA9 from 2009-2014. The 10 pitchers by RA9-WAR produced +15 WAR/+14 RA9, doing slightly better because Cole Hamels gets added to that group and pulls the average up a bit. Webb is the big bust in both samples, offering essentially the same 1-in-10 zero value return as the prospect group. Besides Webb, there weren’t any other players particularly close to zero value, so the elite pitchers offered a slightly higher floor than the prospects, but their overall average performance was actually a little bit worse than the best hitting prospects, and essentially even with the best pitching prospects.
That’s right; for all the talk about unproven risky prospects and established #1 starters, the average performance of six years of an elite pitching prospect lately has been in the same range as the average future performance of six years of one of the best pitchers in baseball. You can re-do the same calculations for other years, and the numbers will fluctuate a bit with age and stuff, but in general, once you’ve identified a “true ace”, you’re probably looking at something in the +15 WAR range over the next six years.
And Creagh/DiMiceli’s work suggests that elite prospects have been performing at similar levels. In other words, even without taking the massive cost differences into account, elite prospects and frontline starting pitchers seem to have about the same long-term values.
