If she lands the role opposite Tom Hanks, it will be her first since "Ocean's Twelve" in 2004, Daily Variety reported.
Hanks, who is producing the film with Gary Goetzman, is playing rogue Texas Congressman Charlie Wilson in the film. Mike Nichols is also reportedly being courted to direct the project, Variety said.
Roberts would portray Texas socialite Joanne Herring, who influenced Wilson to support Afghan rebels in their fight against the Soviet Union.
The film is based the book, "Charlie Wilson's War" written by CBS-TV's "60 Minutes" producer George Crile.
Roberts has been on maternity leave since giving birth to twins in November 2004. Her only work has been voicing characters for the upcoming animated films "Charlotte's Web" and "Ant Bully."