Pac-12 Networks' Mike Yam, Rick Neuheisel and Yogi Roth discuss who they think is at the top of the Heisman race after another big weekend for Marcus Mariota. Oregon's quarterback is joined by Ohio State signal caller J.T. Barrett this week in the award conversation. See new installments of "Nissan Heisman Watch" every Tuesday night on "Pac-12 Football Weekly."