What happened to Curtis Mayfield?

According to this

[url=http://en.wikipedia.org/wiki/Curtis_Mayfield_(Canadian_football]http://en.wikipedia.org/wiki/Curtis_May ... n_football[/url])

he had a good year in 99 with 4 return TDs. What happened to him? Did he do something illegal?

Made the mistake of going XFL if I recall correctly. A lot of players burned bridges doing so...especially coming off a 3 win season then snubbing FA terms

XFL , what a friggin joke that was