Philip RiversThe San Diego Chargers began their 2013 preseason schedule with a home contest against the Seattle Seahawks.

Usually, the outcome of these games are meaningless, but first-year Chargers' head coach Mike McCoy wanted to set the tone for the regular season with a flawless performance from his starters, and for the most part it was mission accomplished.

The offense took the initial drive of the preseason deep into Seahawks territory before settling for a field goal, then the defense came out and immediately harass Seattle star quarterback Russell Wilson forcing them to punt the ball away.

This aggressive syle of play finally allowed the crowd at Qualcomm Stadium to exhale and feel good about their struggling franchise. 

Please, don't overreact to the outcome of the game, as the Seahawks easily defeated the Chargers 31-10. Its sole purpose is to give the coaching staff a reference point to begin evaluating the talent on the football field before deciding which players make the 53-man roster. 

Here are five things we learned from the first preseason game against the Seahawks:

1) Lack of Depth on the Roster

It was pretty obvious after the first quarter that the Chargers lack depth on their current roster. The backups on both sides of the ball performed horribly, but remember that the majority of them have very little NFL experience and should get better over the course of the season. 

2) Manti Teo's Debut

It has been a nighmarish offseason for linebacker Manti Te'o. The last time he played in a competitve football game, his Fightng Irish of Notre Dame were getting outclassed by the Alabama Crimson Tide in the BCS Championship Game, but the oncoming media rush wasn't going to focus on his on-field play. No, it had more to do with Teo's admission that his dying girlfriend was a hoax created by someone he befriended on the internet.

Last Thursday night was Te'o's lone opportunity to silence his critics once and for all. He showed incredible quickness from the inside linebacker position, but Te'o had trouble shedding blocks and getting involved stopping the Seahawks' offense. His pass-defending skills are raw, as Wilson took advantage of his inexperience by perfectly executing a play-action pass for 20 yards to wide receiver Jimmie Kearse that left Te'o flat-footed. 

McCoy announced that his rookie linebacker suffered a foot injury in the game that will keep him out of practice all week and next preseason game. Te'o's debut was a bit disappointing and didn't provide the spark needed to take the spotlight off his back, but he's a rookie and still a work in progress. 

3) The Chargers Have Found Themselves a Running Back

In the disappointing loss to the Seahawks, the Chargers may have added another talented running back to the mix. Fozzy Whittaker showed the patience needed to be an effective runner, as he waited for a hole to open up then utilize his speed to gain an advantage to the outside.

It's only the first game of the preseason, but Whittaker has earned the opportunity to work with the first-team offense and see how he performs under the spotlight. My hunch is that Whittaker will show the determination and talent needed to win a roster spot. 

4) The Chargers Need a Backup Quarterback

Clearly, Charlie Whitehurst showed that he isn't the ideal choice for the backup quarterback position, as he threw two interceptions and was sacked three times in the contest. Whitehurst had trouble readng the pass defense, which forced him to hold onto the football way too long in the pocket and consistently overthrow his receivers all evening long. Add Brad Sorensen's impressive debut in the fourth quarter, and you have yourself a quarterback controversy. 

Sorensen showed an uncanny instinct to scramble away from oncoming pressure and extend a pass play long enough for a receiver to get open. His arm is NFL-caliber and he could turn into something more than a clipboard-holder. Unfortunately, Whitehurst isn't a candidate to be cut this season, as his salary would be a major cap hit for the Chargers, but that doesn't mean Sorensen isn't the heir-apparent to Philip Rivers.

5) The Loss of Danario Alexander

The Chargers' pass offense suffered a huge loss when wide receiver Danario Alexander tore his ACL in practice last week. Now, all eyes will be on wide receiver Vincent Brown, who didn't play in the first preseason game, but is expected to see some action with the first unit against the Chicago Bears next Thursday.

Tight end Antonio Gates is still quarterback Philip Rivers' favorite target down-field, but Brown must show that he can catch the football in heavy traffic. This will force defenses to play more man-to-man coverage on Gates, which should open the middle of the field for him. Malcom Floyd and Brown must become a terrific wide receiver duo if the Chargers have any chance of improving offensively this season.