By Alek Arend A Cowboys rookie is already making a strong impression in minicamp. Mike McCarthy raved about Cowboys’ second-round pick Sam Williams, a defensive end out of Ole Miss, following the rookie’s first practice this week. “I think we’d all agree that Sam Williams looks like a guy that was born to play professional football,’’ McCarthy said, via the Dallas Morning News. “He has the gifts. He has the physical traits. He had two pass rushes today. I know we’re just in helmets, but he was clean in the backfield. He has that kind of ability. He’s in a great place. He’s obviously in an exce…