With all the trade deadline talk and the posts, comments and arguments about the possibility of the Pirates trading prospects for veterans, I thought it might be interesting to take a look back at previous prospects and see how they panned out.
I used John Sickels' 2003 Baseball Prospect Book as the baseline for the study. He's even-handed and well-respected, and most people on this board are at least somewhat familiar with his work. He evaluates a huge number of prospects and assigns letter grades to them, and his methodology and grading has been quite consistent over the years. This lets us evaluate groups of similarly rated prospects together so that we can get a very rough idea of how valuable certain types of prospects might be.
I started out by looking at the C+ prospects from 2003. A C+ prospect is a guy who is a little more interesting than your garden variety C prospect, but still has some serious question marks going against him. These players are generally ranked anywhere from No. 7 - No. 20 in their own organization, depending on its strength, and would rank somewhere between 200 and 400 in baseball. For comparison purposes, the Pirates had six C+ prospects, ranked No. 10 to 15, in 2011:
Sickels assigned a C+ grade to 189 prospects in his 2003 book. I went through and looked up each player's Baseball Reference WAR and put it in a spreadsheet. Here are the results:
- 109 players (58 percent) went on to make at least one appearance in the majors as of today.
- 29 players (15 percent) have compiled least 3 career WAR so far.
- 12 players (6 percent) have exceeded 10 career WAR so far, with two more - C.J. Wilson and Erick Aybar - reasonably likely to join that list.
- 47 players (25 percent) have a negative career WAR, led by Manny Parra with a spectacular -2.7. That's a lot more than I expected.
- Those 189 prospects have produced a total of 260 WAR so far, or roughly 1.4 WAR per person.
Here are the Top 20 C+ Prospects from 2003 in terms of WAR:
Conclusion: It is pretty unlikely for a C+ prospect to become a solid major league regular or starting pitcher, somewhere around 5-7 percent. Almost half will never make the majors at all and most of the rest will have a brief (often extremely brief) career in the bullpen or on the bench.