Players’ multiple roles discussed after Thursday’s practice Defense was the focus Thursday after Nebraska football’s sixth spring practice. Defensive line coach Terrance Knighton said significant practice reps on the D-line are being spread around due to the unavailability of Ty Robinson and Blaise Gunnerson. Benefiting from the situation, Knighton said, are newcomers like Cam Lenhardt, Princewill Umanmielen and Kai Wallin as well as “guys who usually didn’t get a lot of reps in the past,” such as Ru’Quan Buckley and Jacob Herbek. A number of players are showing they can be effective lining up at multiple positions in the first…