Casting Net: Sean Penn eyeing thriller 'Prone Gunman.' Plus: John Hawkes, George Clooney, Ty Burrell

• Sean Penn is in talks to star in the action thriller Prone Gunman, based on the novel by the late French author Jean-Patrick Manchetteabout an international assassin who runs afoul of the organization that hires him after he says he wants out of the business. (Silly assassin; shadowy global organizations are never keen on quiet retirement.) Peter Travis adapted the screenplay; there is no director yet attached. [THR]

• John Hawkes, lately winning Oscar buzz for The Sessions, has signed on for Low Down, a biopic of jazz pianist Joe Albany. He replaces Mark Ruffalo, who had originally been attached to tell the story of Albany’s relationship with his young daughter Amy through the 1960s and 70s. That same daughter co-wrote the screenplay as an adult, with Topper Lilien (Where the Money Is, Dungeons & Dragons). Commercial director Jeff Preiss will make his directorial debut with the project. [Variety]

• George Clooney is in talks to star in Disney’s tightly guarded sci-fi project 1952, which Brad Bird is attached to direct. Damon Lindelof co-wrote the film with EW senior writer Jeff Jensen. [Variety]

• Modern Family‘s Ty Burrell will play a love interest for Bill Hader in the indie dramedy The Skeleton Twins, about grown siblings (Hader and Kristen Wiig) who reevaluate their lives after they both have a near-death experience on the same day. Luke Wilson plays Wiig’s husband. Director Craig Johnson (True Adolescents) cowrote the film with Mark Heyman (Black Swan). [Variety]

• Eric Bana is negotiating to star in the paranormal thriller Beware the Night, about a cop who investigates possessions — and not the drug kind. (Cue scary organ music.) Scott Derrickson (The Exorcism of Emily Rose) will direct from the script he penned with Paul Harris Boardman (The Exorcism of Emily Rose, Urban Legends: Final Cut). Jerry Bruckheimer is producing. [TheWrap, Variety]

• The cast for the drama You’re Not You — starring Hilary Swank as a woman living with ALS (i.e. Lou Gehrig’s disease) and Emmy Rossum as the self-involved co-ed who is hired to care for her — has filled out its cast. Marcia Gay Harden, Loretta Devine, Jason Ritter, Ernie Hudson, Frances Fisher,Ali Larter,and Julian McMahon have all joined the cast, which also includes Josh Duhamel. George C. Wolfe (Nights in Rodanthe) is directing the script from Shana Feste (Country Strong) and Jordan Roberts (Around the Bend), adapted from the novel by Michelle Wildgen. [THR]