He may have to abdicate. Days after declaring himself the “best quarterback in the league,” the oft-injured Washington star suffered a concussion while trying to recover a fumble in yesterday’s pre-season game against the Detroit Lions. Griffin, 25, was tackled and remained on the ground for several minutes. He later left the field on his own accord, and coach Jay Gruden said his QB will return — when healthy — as the team’s starter. But some are wondering if Griffin’s throne will end up being the bench.