Top 50 MLB prospects update

Byron Buxton, Kris Bryant and Carlos Correa remain the top three players in Keith's prospect ranks. Getty Images/USA Today Sports

Not a lot has changed since my Top 100 prospect rankings in January since no official games have been played; as such, no players have "graduated" from the list and we have little new data to consider. But there's one player who wasn't signed at the time of the top 100, and I've shifted a few players around based on substantive differences in stuff or mechanics. For other players, I've provided a brief thought or update on what early 2015 might hold for them.

The Guidelines

• 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. That means Milwaukee Brewers infielder Luis Sardinas, for instance, is ineligible, based on his days on the 25-man roster.

• Only players who have signed professional contracts are eligible.

• I do not consider players with professional experience in Japan or Korea "prospects" for the purpose of this exercise, which means no Jung Ho Kang this year (among others). I also exclude Cuban players who are considered professional free agents by Major League Baseball by virtue of their experience in Cuba's Serie Nacional de Béisbol. This list includes Rusney Castillo and Yasmany Tomas, but will consider Cuban players whom MLB treats as amateurs, such as Roberto Baldoquin (who just missed this list) and Yoan Lopez.

• When ranking players, I consider scouting reports on players -- usually my own, supplemented 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 in recent years, 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 50 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. Giancarlo Stanton has 80 raw power. David Ortiz has 20 speed. Carlos Gomez is an 80 defender. An average fastball for a right-hander is 90-92 mph, with 1-2 mph off for a lefty.

Jan. update: Top 100 indexInsider | Nos. 1-50Insider | Nos. 51-100Insider | By teamInsider | By positionInsider

1. Kris Bryant, 3B, Chicago Cubs

It's not as though Bryant has done anything to defy my contention that he's baseball's best prospect, showing power and a good approach in spring training. He needs some work on his defense, but I don't think that alone is reason to send him down for a few weeks. He remains my pick for NL Rookie of the Year.

2. Byron Buxton, CF, Minnesota Twins

Buxton had a brief stint with the Twins in major league camp, but more important, he's healthy. He missed so much time last year that 2015 will amount to just his second full pro season. He needs the reps, especially at the plate, as the Twins don't want to see a repeat of the Aaron Hicks debacle, where he might have come up too soon and has never recovered from his inability to adjust to major league pitching.

3. Carlos Correa, SS, Houston Astros

Correa got significant playing time with the major league team this month, which I take as a sign he'll be en route to Houston sooner rather than later.