Cappe signed with the Marlins on Friday, Jesse Sanchez of MLB.com reports.
Cappe, who is already 18, waited an extra year to be a part of this signing class, so he is older than most of the top prospects signing Jan. 15. The Cuban shortstop is a glove-first prospect who is very thin (6-foot-3, 178 pounds) and does not project to grow into impact power. He is expected to command a seven-figure bonus.