Rooney Mara and David Fincher were such a united force on
The Girl with the Dragon Tattoo that the assumption is they would never work on a sequel unless were both returning. Fincher famously fought Sony to make sure Mara got the role of hacker Lisbeth Salander, and when it became clear he wouldn't be coming back for more movies, it wasn't expected that she would be back, either. That seemed to be confirmed a couple of weeks ago
when the decision was made to adapt the most recent book in the Millennium series,
The Girl In the Spider's Web, without Fincher, Mara, or even Daniel Craig. But perhaps that was premature?
Speaking with
E!, Mara seems to think she is coming back to the role, or at least she hasn't been told otherwise, saying "As far as I know I'm doing it until someone tells me otherwise."
On the one hand, Mara loved playing Salander so it's possible she would want to do it again, but without Fincher? That seems unlikely but you never know; things might have changed.