The 2009 first-round Draft pick remains with Double-A Altoona, where Sanchez is still in the developmental process on both the offensive and defensive ends.
"Tony has made great progress on all fronts," general manager Neal Huntington said. "We just didn't feel like this was the right time to bring him to the Major Leagues. We've still got some things that he needs to accomplish before he goes to Triple-A."
Learning to call pitches continues to be the biggest challenge for Sanchez, who did not do so while at Boston College. On defense, he is also working to improve the accuracy of his throws and his receiving.
Offensively, the results have been mixed. He's hitting .262 in his first season at the Double-A level, but the power numbers aren't where they were a year ago. After collecting 21 extra-base hits in 59 games last season, Sanchez has just five doubles and two homers in 48 Double-A contests.
"Tony is still driving the baseball," Huntington said. "We're trying to get him to stay in the middle of the field. Sometimes young guys when their power numbers are down try to compensate by trying to yank a little bit more."