He's fat. Not that he's out of shape because he isn't. But if he fights somebody his own weight, the other guy is going to be a lot bigger and stronger.
Just noticed tonight that weight class stops at 265. And Wes said earlier "by the time I step in the ring, I'll be about 270". So he's gaining weight fast after the weigh-in....which says he cut some weight before the weigh-in. A common thing. But if he had to cut a lot, maybe it affected his stamina.
What class is above 265? Maybe Wes needs to be at the next weight class.