Trey Benson, the Arizona Cardinals running back, has been placed on injured reserve due to a knee injury and will miss at least four to six weeks after surgery. During his absence, the Cardinals are expected to rely primarily on Emari Demercado as the main running back. Michael Carter and Zonovan "Bam" Knight are also available as alternatives in the backfield. Emari Demercado, who had been a third-down back, is likely to take over more carries, while Carter might handle more early-down work. The Cardinals have not made any immediate major roster moves to replace Benson but have added running back Jar Jefferson to the practice squad as depth. Benson is expected to return later in the season.