Originally Posted by Mr. Dent
Well according to comicbook Szostak will be Janet...The Wasp.
Of course take it with a grain of salt but it would explain why they're so secretive about her role and would work with the rumors of Hank appearing in a post-credit scene for IM3 and that he has ties to AIM, which play a role in IM3. The one shot we see of Szostak in the trailer also matches Janet's appearance (short dark red hair).
All comicbook.com is doing is retweeting Roger Wardell. And even they point out that Wardell never said anything specifically about Wasp or Janet Van Dyne....it's just bandwagoners jumping to conclusions, as usual.
Also, Jan has always been shown as a brunette or with black hair; I've never seen pics of her as a redhead.