Fernandez, 17, will begin his professional career on Saturday when he joins the Cardinals' Dominican Summer League team. The other three, because of their ages, have signed contracts for 2015 and are subject to approval by Major League Baseball's Office of the Commissioner. Balbuena and Delgado are 16 years old. Nunez turned 17 in mid-May.
The Cardinals have been allotted a bonus pool of $1,866,300 for this yearlong signing period. Clubs that spend in excess of their pool will be subject to fines and future signing limitations.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.