Caleb Downs is expected to be one of the Big Ten’s premier defenders during his first season at Ohio State. Transferring into the program from Alabama, the ball-hawking defensive back has impressed defensive coordinator Jim Knowles mightily during their short time working togehter. “He’s a coach’s dream,” Knowles said after day two of Ohio State’s fall camp. “He understands everything, he picks everything up, he takes the meeting room to the field. He’s locked in during meetings. He takes great notes — he’s a pro. So I think aside from what he does on the field, making all the adjustments and …