Thursday Matchup: Dolphins at Bills Dolphins (4-5) at Bills (3-6) 8:20 p.m. Line: Bills by 1 When your backup running back is averaging 7.3 yards a carry, and leading the team in rushing, it raises the question of whether he should, in fact, be the backup. C.J. Spiller will finally get his chance to be an every-down back for the Bills on Thursday, and by all indications he could be in for a monster game. Spiller, in his third season, has twice topped 100 yards rushing this season, despite never topping 15 carries. Splitting carries with Fred Jackson has been beneficial for both players, but with Jackson ruled out for the week after sustaining a concussion in a loss to New England last Sunday, Spiller could top his career high of 19 carries. That could spell trouble for a Dolphins defense that started off the season well against before falling apart over the last four games. Pick: Bills