‘Yet, despite what would seem to be a formidable challenge from third-year safety Rashad Baker, veteran Troy Vincent appears certain to start Sept. 10 when the Bills open at New England. “Troy’s got the most experience,” defensive backs coach George Catavolos said Monday. “The guy’s played for 15 years. He’s been a very productive player. He’s smart and he’s a good athlete. He’s our leader.”‘