My annual ranking of the top 100 prospects in baseball and the top 10 (or more) prospects in each organization is completely organization-neutral: I don't consider the makeup of the club each prospect plays for when evaluating his potential as a major leaguer.
Many prospects on the list each year will face some obstacles in reaching the majors with their current employers because they're blocked by more established players, or even other prospects higher up in the system, and I've outlined the six prospects most affected by this phenomenon below.
I didn't include pitchers here because the injury rate for starters is high enough that no starting pitching prospect is every truly blocked; Noah Syndergaard and Archie Bradley are one sore elbow away from reaching the majors, and you can bet that the Mets and Diamondbacks, respectively, will have such openings before the 2014 season is out.
1. Mookie Betts, 2B, Boston Red Sox
Betts is the most-blocked prospect in baseball at this point. He's one of the top pure second-base prospects in the game, but he's blocked by Dustin Pedroia, who is among the majors' best second basemen and is under contract through 2021.
Betts is a great athlete and could probably play shortstop … at which he's currently blocked by uber-prospect Xander Bogaerts, and he could probably play center field, at which he's blocked by elite defender Jackie Bradley Jr.