Double-A Montgomery placed Overn on the 7-day injured list May 27 with an undisclosed injury.
Overn, who last played May 23, has had an extreme season both good and bad, as he has a .309/.375/.533 slash line with seven homers and 28 steals in 38 games despite a 32.5 percent strikeout rate. One of the better athletes in the upper minors, Overn's hit tool won't be a strength and could be poor enough that it prevents him from playing regularly at the highest level.