‘It wasn’t his choice to leave Buffalo, but apparently fans there resent his decision to join the Bills’ archrivals in the AFC East. “I’ve gotten nasty mail — `Watch your back when you come to Buffalo,”‘ he said. “I’m thinking they mean maybe a couple of snowballs, but you never know when you get letters like that.” He can’t say former teammate Jim Kelly didn’t warn him. “Jim was the first person I called when I came down here,” Thomas said. “He said, `If you still think you can play, go ahead and do it. But you’re probably going to make a lot of people in Buffalo mad.””