For once, Moorer isn't in immediate danger of getting knocked out cold, but at the same time he loses his usual edge in speed and elusiveness. I find this tricky to pick
Thing to remember though is that Byrd wouldn't be used to Moorer's speed either. The reason Byrd was able to have success at heavyweight is that without exception, he had the faster hands and was usually dealing with opponents with relatively slow hands. But not so against Moorer. In a matchup like this, I always pick the more offensively adept fighter. That's clearly Moorer.
Moorer beats his ass. Byrd was one of the most overrated fighters who ever lived. With no power to worry about, I just see Moorer beating Byrd up with his short, accurate combos.
Moorer didn't have that many great performances either, tbh. A relatively close decision over Axel Schultz and an even bout against Botha, neither of who could punch, suggest that Byrd has a solid chance as well
