This would have been a great fight. Mosley was so fast, powerful, and explosive. Pryor was so relentless and punched from all angles. I see Pryor pressuring Mosley, wearing him down, and winning either a clear decision or a late TKO. There are only a select few I would pick over Pryor at 140 and Mosley is not one of them.
Alexis Argello counterpunched Pryor to death for his win. SSM before his first loss was awesome because he was fearless and blazing fast, would win. SSM after his first loss has lost his aggression and would be defensive too much and lose to an overbearing brawling stlye of Pryor.