49ers-Chargers Betting Preview: What Garoppolo’s Absence Means for San Fran

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Betting market: The market isn’t totally afraid of C.J. Beathard plus the points, as San Fransisco is getting 41% of spread bets at the time of writing (find live odds here).

The line has been moving between 9.5 and 10.5, but it doesn’t appear sharp bettors have taken much of a stance on this one.

This is one of four games this week that has the majority of over/under bets on the under, and there has also been a steam move triggered on the under, which has helped it move from 47.5 to 46 since Tuesday. — Mark Gallant

Injury watch: Running back Matt Breida (knee) and wide receiver Marquise Goodwin (quad) were limited to start the week, while secondary stalwarts Richard Sherman (calf), Adrian Colbert (hip) and Jaquiski Tartt (shoulder) were no where to be found.

Sherman is expected to miss 2-4 weeks.

Chargers defensive end Joey Bosa (foot) said he’s hoping to return in Week 9. He’ll be joined on the sidelines by right tackle Joe Barksdale (leg) and potentially wide receiver Keenan Allen (knee).

The good news is wide receiver Travis Benjamin (foot) and left tackle Russell Okung (knee) are tentatively expected to suit up Sunday. — Ian Hartitz

Trends to know: In general, favorites of at least 10 points in the NFL struggle to cover. Since 2003, these teams are 225-259-10 (47%) against the spread in the regular season, according to our Bet Labs data.

But there's an important split between conference and non-conference games:

• Against non-conference opponent: 68-59-1 (54%) ATS
• Against conference opponent: 157-200-9 (44%) ATS

The Chargers and 49ers play in opposite conferences. — John Ewing

The Chargers lost a tough one against their in-state rival Rams in Week 3.

In Philip Rivers' career, he is 21-11-3 against the first half spread as a home favorite off of a straight-up loss. Since 2012, Rivers is 11-3-1 against the first half spread in this spot, covering by 6.7 points per half. — Evan Abrams

DFS edge: The Chargers’ 28.75 implied team total is the highest mark on the main slate, which bodes well for running back Melvin Gordon, considering the Chargers are massive 10-point favorites.

Gordon leads the Chargers with 36% of their red-zone opportunities and he presently owns the highest ceiling projection among running backs in our Week 4 FantasyLabs Models. — Justin Bailey

Bet To Watch: Under 46

The logic behind this bet starts with Beathard. Under 49ers head coach Kyle Shanahan, Jimmy Garoppolo was averaging 2.15 more yards per pass attempt than Beathard is over the past two seasons.

When it comes to gaining yards downfield, it is not like Beathard hasn’t been effective; he just isn’t Jimmy G.

Under Shanahan, Garoppolo averaged 0.9 more pass yards at the spot of reception than Beathard (seventh in NFL vs. 18th for C.J.) and 0.6 more passing yards after the reception (second in NFL vs. 10th for C.J.).

One area where the Niners will struggle is getting their playmakers open downfield without Garoppolo under center running play action.

This season, 33.6% of Garoppolo’s dropbacks featured play action, the second-highest rate in the NFL and Garoppolo was averaging 11 yards per attempt on those plays (fifth-highest).

Don't expect that same level of success with Beathard, who's averaged just 6.3 yards per attempt overall in his five starts.

In Rivers' career as a starter at home, he has faced a team averaging fewer than 6.5 yards per attempt 17 times, the under is 10-6-1, including 8-3-1 over the last decade, going under the total by an average of 5.8 PPG. — Evan Abrams

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Editor’s note: The opinions on this game are from the individual writers and are based on their research, analysis and perspective. They are independent of, and may not always match with, the algorithm-driven Best Bets from Sports Insights.