San Diego Chargers at San Francisco 49ers

Saturday, 8:25 p.m. ET, at Levi’s Stadium, Santa Clara, Calif. – TV: CBS

*TV announcers: Ian Eagle, Dan Fouts, Jenny Dell

*Keys to the game: It’s a battle of attrition for two teams limping to the finish line with a slew of injuries. The Chargers lost WR Keenan Allen to a broken collarbone, and RB Ryan Mathews is expected to miss the game with a sprained ankle.

That leaves QB Philip Rivers exposed to a defense that can still dominate in the trenches. He has struggled with his accuracy of late and his receivers are not consistently gaining separation. But the 49ers also took a hit with standout rookie LB Chris Borland shut down for the season and DE Ray McDonald released midweek.

As sporadic as the offense has been, San Diego coach Mike McCoy has been pleased with the overall play on the other side of the ball. The Chargers gave up three completions of 30-plus yards to Peyton Manning last week but otherwise held up well, and the run defense allowed just 2.8 yards per carry. The 49ers may be without RBs Frank Gore (concussion) and Carlos Hyde (ankle), leaving journeyman Alfonso Smith running with the first team.

Embattled QB Colin Kaepernick clearly misses the Pistol formation, as he is uncomfortable throwing consistently from the pocket and isn’t getting outside as often to utilize his dual threat abilities.

*Matchup to watch – 49ers offensive line vs. Chargers OLB Melvin Ingram: Clearly the Chargers’ most dynamic pass rusher, Ingram will seek mismatches against an offensive line that allowed six sacks and 11 quarterback hits last week. Some of those fall on Kaepernick, who too often lacks decisiveness in the pocket.

*Player spotlight – 49ers LB Nick Moody: Called for a controversial roughing penalty last week, the second-year player is in line for increased snaps with Borland out.

*Fast facts: Chargers TE Antonio Gates needs 145 receiving yards to become the fourth tight end in NFL history to reach 10,000 for his career. … Kaepernick has a 58.1 passer rating with no touchdowns and two interceptions in the fourth quarter of games within seven points this season.

WHO WILL WIN AND WHY

The 49ers are 3-3 at home and playing a meaningless game for the first time under coach Jim Harbaugh. How they respond will be indicative of how far the situation has unraveled. The 49ers still have superior talent at most spots, and our bet is Harbaugh rallies his troops.

*Our pick: 49ers 23-19