The annual ranking of baseball's Top 100 Prospects is assembled by MLBPipeline.com Draft and prospect experts Jonathan Mayo, Jim Callis and Mike Rosenbaum, who compile input from industry sources, including scouts and scouting directors. It is based on analysis of players' skill sets, upsides, proximity to the Majors and potential immediate impact to their teams. Only players with rookie status entering the 2016 season are eligible for the list. The rankings follow the guidelines laid out by the Collective Bargaining Agreement, in terms of who falls under the international pool money rules: Players who were at least 23 years old when they signed and played in leagues deemed to be professional (Japan, Korea, Taiwan, Cuba) are not eligible.
Brought into the A's organization as a key piece of the Josh Donaldson deal, Barreto enjoyed a strong showing at Class A Advanced Stockton last year, batting .302/.333/.500 with 13 home runs. Barreto, who won't turn 20 until Feb. 27, will likely begin the 2016 campaign in Double-A Midland. The shortstop is expected to diversify his skillset there by clocking in time in center field, where he occasionally played in winter ball.
Manaea is considered the closest to being big league ready of the three and will enter Spring Training as a "wild card" to make the rotation out of camp, manager Bob Melvin said recently. Either way, the 6-foot-5 southpaw, acquired last summer in the Ben Zobrist trade, is expected in Oakland at some point this season.
Manaea, 23, excelled early in his A's career, posting a 6-0 record and 1.90 ERA in seven starts with Midland following the trade. He made six more starts in the Arizona Fall League, finishing with a 3.86 ERA and 33 strikeouts in 25 2/3 innings.
Olson, meanwhile, returns to big league camp a second time after hitting .249/.388/.438 with 17 home runs and 75 RBIs in his first season at the Double-A level. During his time with Midland, Olson not only manned first base but got experience in right field, making 59 starts there. He's likely ticketed for Triple-A Nashville to begin this season.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.