As Screenrant's Rob Keyes pointed out (see link below), it's possible we'll see a younger version of Pym in 'Ant-Man'. The theory goes - part of the movie will show Pym inventing the Ant-Man tech in the 1960s and then the timeframe would shift to the present day. The only other part in the movie that's confirmed is Scott Lang (played by Paul Rudd). Michael Pena and Evangeline Lilly are also reported to be close to signing on to 'Ant-Man', as well.
Oddly enough, it's that represents the longest-in-development project from Marvel Studios to date, and since the beginning, Edgar Wright has been set to write and direct. Over the years, beginning long before Iron Man even hit theaters in 2008, there have been casting rumors and fan wishlists for who should play the littlest Avenger who Wright says can "kick your ass one inch at a time."
'Ant-Man' opens on July 17, 2015.