Over 33 games with Triple A affiliate Lehigh Valley this season, Franco, who is expected to play third base, recorded a .355 batting average with four home runs and 24 RBIs.
MLB.com ranked Franco the Phillies' No. 3 prospect in 2015.
"This was a baseball decision based on Maikel's development and performance," Phillies general manager Ruben Amaro Jr. said. "We believe he is ready for the next step."
Philadelphia has yet to announce a corresponding roster move to make room for Franco. The Phillies begin a three-game series against the Arizona Diamondbacks in Philadelphia on Friday night.
The Phillies sit in last place in the NL East with a 13-23 record.