As part of his 2014 Mets' Power Rankings, Patrick Flood discusses the odds regarding Matt Harvey and Zack Wheeler becoming good, or even useful major leaguers by comparing them to similar prospects, by ranking, of years past.
He compares the 50 pitchers who have ranked between #20 and #20 on Baseball America's prospect list between 1998 and 2007 and found:
The average is 7.2 WAR per player. If we take these subgroups and combine them into three large groups:
...That is to say that half the time, you end up with a single Pelfrey or worse.
- 40% were ultimately disappointments: middling relievers, sub-replacement starters, and the pitchers who never made it to the majors
- 32% became useful pitchers: setup men, closers, or Pelfreys
- 28% became good pitchers: aces, all stars, and quality starters
As for Familia, who BA ranked in the #90 range:
The average career WAR is 2.5. If we take these sub-groups and put them together into three bigger groups:
In other words, 61% of pitching prospects similar to Jeurys Familia ultimately disappoint, either by never reaching the majors, having short careers, or by becoming middling relievers. 61% fail. 61%! The odds are against Familia amounting to anything.
- 61% were disappointments: Sub-replacement level pitchers, poor relievers, and the pitchers who never made it to the majors
- 31% become useful pitchers: Middling starters or decent relievers
- 8% become good pitchers: A top reliever or a good starting pitcher