The Wrap reports that Josh Brolin will co-star in Sicario, which shoots this summer. It also reveals the particulars of each role. The mission is a CIA-fronted one, with Blunt starring as a Tucson SWAT officer who is recruited on a cartel-destroying mission with the aforementioned duo of mercenaries, one of them played by Del Toro. Brolin would play the CIA operative who recruits Blunt, which means there is still one mercenary role left to be cast, and a couple of bad guys who might require big name actors as well. In other words, casting is not be complete for this project.
Brolin's having a pretty big week. Yesterday it was revealed that he was the name-acting Marvel had been courting for so long to play Thanos, the big baddie in the next couple films. Brolin's only providing a voice for Guardians Of The Galaxy, but he's shooting Sicario this summer. Given that he's supposed to actually be in Avengers: Age Of Ultron, which is shooting now, you can guess that his part in that summer blockbuster is not very big.
Brolin will next be seen in Paul Thomas Anderson's Inherent Vice and the exploration adventure Everest.