The actor, who is currently shooting World War Z, is being tapped to play a CIA operative-turned-assassin in the film, Variety reports.
Based on the popular Mark Greaney novel, The Gray Man tells the story of a covert agent who is targeted for elimination himself and must go on the run.
The screenplay, which has been written by newcomer Adam Cozad, made the annual 'Black List' of the industry's best unproduced screenplays in 2010.
Pitt recently praised his partner Angelina Jolie for being organised, crediting her with keeping their extensive family in check.
In mid-July, Pitt and Jolie were rumoured to be considering marriage, though those reports were quickly shot down by a friend of the couple.
Pitt can be seen next in Moneyball, which is due for release on September 23 in the US and November 25 in the UK.
Watch the trailer for Brad Pitt's Moneyball below: