Agent blasts top Yankees prospect: ‘Stabbed me in the back’

According to the person who advised Justus Sheffield when he was an amateur, the Yankees’ top-rated pitching prospect, by MLB Pipeline’s ranking, is a “bastard” with “no backbone, no integrity whatsoever.” David Sloane, a longtime agent, represented Sheffield and his brother, Jordan, when the two were drafted. He hasn’t spoken to either since 2014, a…