Quarterback Philip Rivers will start Saturday for the San Diego Chargers despite a back injury that might be more severe than the team has indicated.

ESPN cited a source Thursday in reporting that Rivers is “battling a back injury that is bigger than people realize.”

Rivers did not practice Wednesday and is on the injury report with back and chest injuries.

But Rivers said he plans to play Saturday at San Francisco in what could be the final meaningful game of the season for the Chargers after consecutive home losses.

“We still got a lot of fight in us,” wide receiver Eddie Royal stressed.

The best way for the Chargers to reach the postseason is to win this week and end the season with a road victory at Kansas City. If that happens, and Baltimore or Pittsburgh or Cincinnati falters, the Chargers could have a January pulse.

“We’re still not in a great position,” said first-year offensive coordinator Frank Reich. “We just got to take care of business and try to go 1-0 this week.”

Among the reasons the Chargers are scrambling — their offense is in shatters. Running back Ryan Mathews (ankle) did not play last week and might miss another game and Rivers is clearly not himself.

“It’s not about blame,” said Reich, a former NFL quarterback. “It’s about accountability. We have to stick together, but each person, individually, has to find a way to do better.

“I’ve been on teams that went to Super Bowls and ones that were 2-14,” Reich said. “And it’s crazy how thin the line is between those two.”