Thurman too wide, can't fight inside, might be vulnerable to the body, no height or reach advantage when he wants to run; gets knocked out unless he lands something big.
And even if he did, how does it help him? Mosley had a great chin. I don't think Shane needs to display that chin too often though. Yeah, I think Thurman gets stopped inside of 6.
If Forrest can hurt him and discombobulate him for the rest of the fight Thurman has a shot. Unlikely but possible.
Thurman's money punch is his left hook. If Shane can handle Oscar's best left hook, he can handle Thurman's.
