An 18-year-old infielder from Arlington Country Day School in Jacksonville, Fla., Baez was selected ninth overall by the Cubs and signed for a $2.7 million bonus, the Chicago Tribune reported Monday.
He was ranked No. 16 on MLB.com's list of this year's top 50 Draft prospects. A shortstop in high school, Baez could move to third in the professional ranks.
The Cubs also inked their second-round pick, Daniel Vogelbach, a left-handed hitter from Fort Myers, Fla., and 14th-rounder Dillon Maples, a right-handed high school pitcher from North Carolina.
The Tribune reported their bonuses as $1.6 million and $2.5 million, respectively, the latter a record for a player taken after the second round. Maples was believed to be a strong commitment -- as a kicker for the football team -- to his home-state University of North Carolina.
"This commitment to the draft is significant in a couple of ways, both in terms of financial investment, which was substantial, and the quality of players that are joining our organization," Cubs Scouting Director Tim Wilken said in a statement. "It's a clear statement from our owners, the Ricketts family, that the Chicago Cubs are committed to drafting the very best players and developing their own players within the system."
Chicago also signed Shawon Dunston Jr., the son of the No. 1 overall pick by the Cubs in 1982, for $1.275 million, according to Baseball America. Dunston, a high school outfielder, was drafted in the 11th round.
Vogelbach, 18, hit .459 (39-for-85) with six doubles, four triples, 17 home runs, 50 RBI and 40 runs scored in 32 games in 2011 for Bishop Verot High School in Florida. The first baseman was named by Baseball America as the third-best power hitter among all high school eligible players in the draft.
Maples, 19, was named the 2011 Gatorade North Carolina High School Player of the Year after going 9-1 with a 0.93 ERA for Pinecrest High School this season. He had 143 strikeouts in 68.2 innings and also posted a .431 batting average with seven home runs and 31 RBI.
"This is one of the most talented draft classes I've ever seen signed by an organization," Wilken said. "We believe we have three first round talents in Javier Baez, Daniel Vogelbach and Dillon Maples, and also believe we have secured one of our deepest draft classes ever to compliment that trio."
Dan Cichalski is an editorial producer for MLB.com. Joey Nowak is a reporter for MLB.com. Follow him on Twitter at @joeynowak. This story was not subject to the approval of Major League Baseball or its clubs.