Every team has players it can count on. The San Francisco 49ers are no exception.
Everyone knows Patrick Willis and NaVorro Bowman are primed to be two of the best inside linebackers in the NFL in 2013, assuming they stay healthy. And San Francisco's offensive line should, once again, have no issues opening big holes for Frank Gore and the 49ers running game.
But not all of San Francisco's players are marked with as much certainty. Some are facing major question marks or new roles they've never had to fill.
The following are five 49ers who will make or break San Francisco's season.