Top 50 MLB prospects update

Nationals pitching prospect Lucas Giolito and Rangers outfield prospect Nomar Mazara have both looked good this spring. Getty Images, USA TODAY Sports

Not a lot has changed since my Top 100 prospect rankings were posted in February. In fact, the rankings themselves remain the same as they were six weeks ago, as no material has changed; we don't have any new prospects to add, and no player on the list has suffered an injury or other setback that might knock him down. Consider this an update, as I've provided a brief thought for each prospect about anything from his spring work to recent transactions that could affect him to what might be in store for him in 2016.

The full scouting profiles for all 50 players can be found here.

The usual 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.

• 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. 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. As such, this list excludes Byung Ho Park and Kenta Maeda, but it will consider Cuban players whom MLB treats as amateurs, like Yusniel Diaz (who is in the rankings) and Yadier Alvarez.

• When ranking players, I consider scouting reports on them -- 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 that are closer to the majors. This better reflects how these players are valued now by front offices and scouting departments, and it gives me a chance to deliver more information on prospects whose names or scouting reports might be new to you.

• I use the 20 to 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. Giancarlo Stanton has 80 raw power, for instance. David Ortiz has 20 speed. Andrelton Simmons is an 80 defender with an 80 arm. An average fastball for a right-hander is 90 to 92 mph, with 1 to 2 mph off that for a lefty.

Updated Top 50 prospects

lastname1. Corey Seager, SS/3B
Los Angeles Dodgers
Age: 21 (4/27/94) | B/T: L/R
Height: 6-4 | Weight: 215

Seager appears set to be the Dodgers' everyday shortstop in 2016. His defense might fall short of average, but no one minds a below-average glove when the player can hit like Seager can.

lastname2. Byron Buxton, CF
Minnesota Twins
Age: 22 (12/18/93) | B/T: R/R
Height: 6-2 | Weight: 190

Buxton is going to be the Twins' center fielder to start the year, and should be a plus defender right out of the chute. At the plate, he needs to work on pitch recognition to ensure he can make more contact in his second go-round in the bigs.

lastname3. Lucas Giolito, RHP
Washington Nationals
Age: 21 (7/14/94) | B/T: R/R
Height: 6-6 | Weight: 255

Giolito impressed everyone in big league camp, but there was no room in the Nats' rotation for him -- not that jumping him to the bigs was necessary -- and whether he starts in Double-A or Triple-A, he should be ready to contribute to the big club should they have the need for another starter at some point this summer.