When Zack Snyder left the movie to spend more time with his family following his daughter’s suicide, Whedon was tasked with overseeing the reshoots.
After Avengers: Age of Ultron, Whedon made a clean break from the MCU, leaving Captain America: The Winter Soldier directors Joe and Anthony Russo to take over on Earth’s Mightiest Heroes.
While Batgirl may have been the DCEU movie that caught Whedon’s eye first, he was also hired during Justice League’s post-production to rewrite some additional scenes.
Once those are completed, he’ll turn his attention to Batgirl, and if Warner Bros reveals that Whedon will be involved with other DC projects, we’ll be sure to let you know.