Baez will join the team for its upcoming series in Colorado.
The 21-year-old was the ninth selection of the 2011 draft. At the start of the season, he was ranked the No. 4 prospect by Baseball Prospectus, No. 5 Baseball America and No. 7 by MLB.com.
"Baez generates incredible bat speed, resulting in big power," his MLB.com scouting report says. "He also has the ability to hit for average, if he is able to develop more plate discipline. But Baez is a good bad-ball hitter, and he often finds a way to get his bat on the ball in spite of his aggressiveness."
Though he was drafted as a shortstop, Baez will begin playing at second base, according to Bruce Levine of 670 The Score in Chicago. The Cubs began training Baez at second this season, and he played 16 games there for Triple-A Iowa.
Baez batted .260 this season in Triple-A, with a .510 slugging percentage. He had 23 home runs and 80 RBIs in 104 games.
Baez is the second top prospect to be called up by the Cubs in recent weeks. The team also promoted Arismendy Alcantara in early July. Alcantara has been playing second base but also has the ability to play the outfield.
- Dan Gartland