According to Avengersnews.com, it isn't yet clear what superhero costume the erstwhile Sawyer would slip into, but the site has compiled a list of possibilities based on hints it’s received.
The website breaks it down as such:
Clint Barton/Hawkeye (maybe a S.H.I.E.L.D. member in The Avengers with a starring role in the S.H.I.E.L.D. spin-off or a future Avengers sequel.) Jeremy Renner has recently also been rumored for the Hawkeye role.
Timothy "Dum Dum" Dugan (important S.H.I.E.L.D. member in The Avengers and its sequels, and lead role in the S.H.I.E.L.D. spinoff).