Rashida Jones just signed on for a new television pilot for TBS. There may have been concerns about scheduling in the event the show goes to series.
If she had been serious about getting the Wasp role, she shouldn't have signed on to a tv pilot yet. Nearly all of them aren't picked up, and more than half each year end up getting canceled before the first season finishes. Being in a successful movie would greatly enhance her career more than some show.