Adam Simon (Synapse) penned the script, and Dito Montiel (A Guide to Recognizing Your Saints) will direct. Dawn Krantz, Stephen McEveety and Jon Burton have been brought on to produce.
"When I read the script for the first time I knew it was something very special," Krantz said in a statement.
Man Down will begin production in New Orleans in October. LaBeouf will next appear alongside Brad Pitt in Fury, and Oldman is scheduled for Child 44 in 2015. Mara will portray Sue Storm, aka the Invisible Woman, in the upcoming reboot of The Fantastic Four.