Welcome to the fourth annual edition of my rankings of the top 100 prospects in baseball. With a slew of impressive debuts from top prospects in 2010, including the top five prospects from this list last year (Jason Heyward, Stephen Strasburg, Buster Posey, Carlos Santana, and Mike Stanton), the top of the rankings has an entirely different look to it, with most of the high-upside minor leaguers still working in A ball last year.
The rankings are limited to players who still have rookie eligibility; that means they have yet to exceed 130 at-bats or 50 innings pitched in the majors and have not yet spent 45 days on the active roster of a major league club, excluding call-ups during the roster expansion period after Sept. 1. (One player affected by this is the Mets' Jenrry Mejia, who no longer qualifies as a rookie.) Only players who have signed professional contracts are eligible. When ranking players, I consider scouting reports on players -- usually my own, supplementing with conversations with other scouts and front-office executives as needed -- as well as performance, adjusted for age and context. I've made one adjustment in my ranking philosophy, favoring higher-upside prospects over lower-ceiling prospects who are closer to the majors. This better reflects how these players are valued now by front offices and scouting departments and gives me a chance to deliver more information on prospects whose names or scouting reports might be new to you.
I use the 20-80 grading scale in these comments to avoid saying "average" and "above average" thousands of times across the 100 player comments. On that scale, a grade of 50 equals major league average; 55 is above-average, 60 is plus, 45 is fringy or below-average, and so on. Mike Stanton has 80 raw power. Bengie Molina has 20 speed. An average fastball for a right-hander is 90-92, with 1-2 mph off for a lefty.
I've included last year's rank for players who appeared in the top 100 last offseason. An "ineligible" player (IE) was still an amateur at this time last January, whereas an "unranked" player (UR) was eligible but didn't make the cut. I've also tagged players who were on last year's sleepers list or list of 10 players who just missed the cut.