A listing on Television Show Auditions states that the Avengers spinoff will go in front of the cameras in Los Angeles early next year, which could put it on course for a Comic-Con screening.
Former ER actress Ming-Na Wen will play the lead role of Agent Melinda May in the ABC pilot, with Clark Gregg starring as Agent Phil Coulson, a part he played in several Marvel Studios movies.
Avengers helmer Whedon is writing the pilot along with brother Jed (Spartacus) and Maurissa Tancharoen (Drop Dead Diva), and is also expected to direct.
The show will be set within the Marvel cinematic universe, but stand alone from the films, depicting the titular organisation going up against super-powered threats.
S.H.I.E.L.D is targeted for ABC's fall 2013 season.