Cary Grant in a Western?

The Trivia section mentions that Hawks had originally wanted Cary Grant for the role of Cherry. Huh? He'd obviously enjoyed working with him before, but using Grant in a Western makes about as much sense as using Noel Coward or Bela Lugosi. And why would Grant have accepted a supporting role at that stage of his career? Yes, I know, the character's screen time was slashed by Hawks because of his displeasure with John Ireland, but it still had to be supporting of Garth & Dunson. Can anyone shed light on what the director's thinking might have been to have wanted Grant?
May I bone your kipper, Mademoiselle?