Although nothing is official on its top 10 selections, the organization is confident it will reach deals with each of them by the end of June.
Barrett is a left-handed-hitting center fielder from Kentucky. Fernandez, who attended Nova Southeastern University, is listed as a left fielder, but he may wind up playing second base.
• Marlins' 2015 Draft selections
Also signed are right-hander Kyle Keller (18th round), shortstop Alfonzo Giovanny (21st), righty L.J. Brewster (22nd), left-hander Trevor Lacosse (23rd), righty Obed Diaz (26th), shortstop Taylor Munden (27th), lefty Jeff Kinley (28th), righty Ben Meyer (29th), shortstop Joseph Chavez (30th), third baseman Kris Goodman (32nd), right fielder Brandon Rawe (34th) and lefty Gunnar Kines (36th).
First-round pick Josh Naylor is not eligible to sign until he graduates high school, which will be on June 25. The first baseman from St. Joan of Arc Catholic in Canada, who impressed in batting practice on Saturday at Marlins Park, is expected to reach agreement shortly after he graduates.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.