Five things we learned about the Chargers this preseason

Philip Rivers said he didn't mind an extra little helmet shove from Seattle's Frank Clark in his final preseason tune-up.

His team should take that same fighting attitude to the regular season. Rivers has a few more targets to throw to, but one noticable loss -- suspended star Antonio Gates -- to start the season. That's okay; the much-improved defense looks reasdy to shoulder more responsibility.

Through four exhibition games, they've looked the part of AFC West challenger. Whether they can unseat the reigning champs in Denver remains to be seen.

With the regular season set to kick off on Thursday, here are the five most important things we learned from the Chargers' preseason.

1. Melvin Gordon isn't ready to start

This Melvin Gordon looks nearly unrecognizable. He's neither decisive nor explosive -- and those are two traits the Chargers wanted to see from their top draft pick. The good news? San Diego's running back stable is deep if the rookie needs more time. But their one-cut zone-blocking scheme isn't exactly tough to digest.

2. Melvin Ingram is absolutely ready

Ingram looked like a new man when he reported to Chargers Park for training camp. That new physique has paid immediate dividends; Ingram was all over Carson Palmer when the Bolts played the Cardinals in exhibition action, for instance. Head coach Mike McCoy said the outside linebacker is "on fire." For San Diego's sake, he hopes Ingram never cools off.

3. Stevie Johnson could light it up

Eddie Royal is no longer plying his trade as Philip Rivers' security blanket in the slot. Enter Stevie Johnson, who slimmed down to his old high school playing weight to fit McCoy's ideal mold. An offseason of intense training has slimmed Johnson down, but hasn't compromised his trademark toughness. Rivers will absolutely love him.

4. Antonio Gates' suspension will be tough on the offense

The NFL pinched San Diego's star tight end for banned substances a few months ago. Antonio Gates maintains his innocence, but his team is guilty of not grooming a viable replacement behind him. Ladarius Green is capable, but nowhere near the red-zone threat Gates is. The rest of the group hasn't inspired much confidence this preseason. The Chargers might want to comb through final roster cuts.

5. Rivers will be a Charger, no matter what

First, there was the initial contract drama. The trade rumors soon followed -- Philip Rivers reportedly wanted no part of the Chargers if they relocated to Los Angeles. Then, after a summer of negotiating, the Chargers did what any team would and locked in their franchise passer. He'll be part of the fold no matter what city the team calls home.