The good news for the Chargers is the magic number of 30 carries applies against the Broncos. In Denver's 13 victories only 2 teams got to 30 carries, and one was San Diego. In the Broncos 3 losses, each team carried the ball over 30 times. It's well known that the game plan to beat Denver is to keep Manning off the field. It's much harder to actually run the ball effectively.
Not only do the Chargers lead the league in most yards per drive, but they're 4th in the NFL in rushing attempts, with 31 per game. This bodes well for Sunday, as they don't need to really alter their game plan to beat Denver. In Week 15, San Diego was able to manufacture 44 carries for 177 yards. While those numbers might be an outlier, the Chargers should run early and often.
Denver will be without their best player and run defender in Von Miller. It looks like they'll also be without another key player along the line, DE Derek Wolfe. The gameplan should be to get to the edges and run, run, run. The last time the Chargers tried to run right, Miller embarrassed the combination of Gates/Green/Fluker, constantly beating them and making plays at or behind the line of scrimmage. Expect the Chargers to run right at Shaun Phillips, and be successful. In Week 15, the team totaled 11 carries for 61 yards when running at Shaun Phillips.
Attack the "Other" Defensive Backs
In my opinion, the Broncos have 2 of the better cover corners in the league in Dominque Rodgers-Cromartie and Chris Harris Jr. They're good, borderline great. The rest of the secondary? Not so much.
Champ Bailey is back, yes. The best corner in the last decade is a shell of his former self. The rest of the secondary, is either inexperienced, or a mismatch for the Chargers pair of Tight Ends. In fact, once you get past the Broncos first two Cornerbacks, they're 27th in the league in DVOA at defending "other wide receivers".
Last week, Ladarius Green played 50 snaps (!) and Antonio Gates played 40 snaps. I'm expecting a lot of targets towards the middle of the field directed towards those two Tight Ends. If the Chargers are able to run the ball, and stay ahead of the chains, then Gates/Green should be able to operate underneath and keep the drives alive.
Keep Rivers Upright
The one thing that's hurt the Chargers is untimely sacks or pressure. Either Rivers has gone down, or was forced to leave the pocket before he wanted to. Denver is actually worse than San Diego in Adjusted Sack Rate, ranked 21st in the NFL. They're also 21st in DVOA against the pass. As we're well aware, after watching 17 games of the Chargers, the two are correlated. A lack of pass–rush forces the Defensive Backs to cover longer. While I'm not expecting the game plan to be for Rivers to drop back 35+ times to throw it, when he does drop back, it'll be important that he stays upright and drives aren't stalled.
Can the Chargers Win?
Yes. San Diego went to Denver before with a masterful game plan and came away victorious. The Chargers can't afford a slow start or costly mistakes. They're just not good enough to overcome those. If they're able to do these three key things on each side of the ball, the chances of them winning are very good. If they don't execute, then we'll be talking about the draft this time next week. No one wants to talk about the draft while real football is still being played.