According to Jason Parks of Baseball Prospectus, Gregory Polanco is being promoted to Altoona.
https://twitter.com/ProfessorParks/status/345286134898774016
Polanco has been having a great season, hitting for a .312/.364/.472 line in 218 at-bats, with 17 doubles and six homers. The offensive numbers are even more impressive when you consider that Polanco has been playing in one of the most pitcher friendly leagues in all of minor league baseball. We recently rated him the second best prospect in the system behind Jameson Taillon now that Gerrit Cole has graduated. The jump to Double-A is the most difficult to make for any hitter, so this will be a huge test for the 21 year old outfielder. If he handles it well, he could make the jump to Indianapolis at the start of next season, and arrive in Pittsburgh by the middle of 2014.