49ers vs. Chargers: Week 4 preview for San Francisco

49ers X-factors and players to watch

The most significant variable in Sunday’s game is the San Francisco 49ers’ new starting quarterback:

QB C.J. Beathard

When Beathard lined up under center in Washington last season, he was vying to become the 49ers’ long-term starting quarterback. There will be less pressure on the second-year QB this year, as Beathard knows he’ll be relegated to a backup role after the conclusion of the season. Although the 49ers are far from a complete team, San Francisco had playoff aspirations with Garoppolo as their starting QB. Beathard’s play will determine whether the Niners’ 2018 season will have significant meaning, or whether the team will be playing for draft position in December.

49ers’ Linebackers

WILL linebacker Reuben Foster may have been a bit too excited for his first post-suspension game, as the linebacker over-pursued plays and missed as many tackles as he made. Fellow LB Malcolm Smith‘s return to the field was even worse, although his errors were mostly mental, both in pass coverage and against the run. Rookie MIKE linebacker Fred Warner also needs to play better on Sunday, after missing a number of key tackles last week. Overall, the 49ers’ talented linebacker corps needs to take a major step forward against Los Angeles.

RB Matt Breida

Although he has continued to split carries with Morris, Breida began Week 4 as the NFL’s leading rusher, thanks to a league-leading 8.6 yards per carry. Despite rushing the ball only 32 times, Breida also leads the NFL with six runs of over 20 yards. The 49ers will likely lean on their running game with Garoppolo out, and given Beathard’s propensity to throw to his running backs, Breida should see more action in the passing game as well — provided he’s healthy enough to play.

49ers’ Secondary

Even at full strength, San Francisco’s secondary has struggled over the beginning of the season. With Sherman out and Tartt doubtful for Sunday’s game, at least two backups will start for the 49ers in Los Angeles. If Colbert is inactive, the Niners will likely start a pair of converted college cornerbacks — Exum and Reed — at the team’s two safety positions. The 49ers’ makeshift secondary will have their hands full with wideouts Mike Williams and Tyrell Williams, along with Chargers star wideout Allen, who is officially listed as questionable but is likely to play on Sunday.