Brad Pitt: How Is He Being Considered for Best Actor?

Brad Pitt does play Benjamin Button in "The Curious Case..." for at least 30 minutes. But to say that he "struggled" through the part at every age is a lie. He is assisted by Peter Donald Badalamenti II, Robert Towers, Tom Everett, Spencer Daniels, Chandler Canterbury, and Charles Henry Wyson. Six actors help Brad Pitt in this part. I found Pitt's short screen time less than convincing to say the least, and even if he was playing every single age of Benjamin, he would not have been any more impressive. I don't understand how he's overshadowing Sean Penn, Mickey Rourke, and Josh Brolin here. He's just being considered on his status as a model here.