The San Diego Chargers have a big decision to make with their quarterback Philip Rivers.

Rivers is in the final year if his contract in which he will make $15.75 million in base salary. And then, he is set to become a free agent.

The Tennessee Titans have shown a lot of interest in acquiring the veteran quarterback this offseason via trade.

Here are five reasons the Chargers should trade Rivers this offseason:

1. Why not?

The Chargers have missed the playoffs four of the last five seasons. They haven't even had a 10-win season since 2009, which was also the last time they won the AFC West. Which begs the question, why keep an aging Rivers for high money if you're not winning anyway? Remember Herschel Walker? The Dallas Cowboys knew they weren't going to win with him, so they traded him away and got big value. It's not Rivers' fault by any stretch of the imagination. Rivers is a great quarterback, but the reality is the Chargers aren't benefiting one bit from having him on the roster right now -- it's just a fact.

2. Cap Space

The most likely scenario that will take place is a franchise tag, and then possibly new contract. The Chargers probably won't let Rivers walk after this season, thus using the franchise tag on him keeping him around for at least one more year. Using the franchise tag on Rivers after next season will cost about $19 million. There were no quarterbacks franchise tagged this offseason for a reason: It cost a ton of money. The Chargers ranked 30th in rushing yards and 26th in rush defense last season. They have to save cap space because they have a lot of other issues to fix for the future.

3. Age

Rivers is currently 33 years old. After his contract expires, he will be 34. If the Chargers decide to franchise tag him, he will be 35 when that all plays out. Meaning, the Chargers would be investing over $34 million in a quarterback who turns 35 years old with an expiring contract. Rivers' stock is high right now having passed for 31 touchdowns last season, so his value won't be any higher than it is right now. Waiting to trade Rivers in two years when he's 35 would only decrease his return value, and the Chargers would be taking a huge risk if they don't trade him now because he may just walk on his own.

4. Let the Rebuilding Begin

This kind of goes back to No. 1 with the Cowboy and the Walker trade. The Chargers are an average team that just isn't ready to win now. They need running backs, a better defensive line, more wide receiver depth and Antonio Gates isn't getting any younger. It's time to rebuild, save cap space and get draft picks now. Continuing to invest into an average team that is just going to miss the playoffs with Rivers is the definition of insanity -- doing the same thing over and over again expecting different results.

5. Better Get Value Now

The Chargers shouldn't just trade Rivers so they can save money and rebuild, but they better make a decision quick because Rivers may leave once he becomes a free agent. Sure, the Chargers can place the franchise tag on him for one year, but then what? As previously stated, Rivers is a great quarterback who ranks in the top 10 at his position today. The Chargers should have no problem finding a team interested in Rivers this offseason. Rivers has also said that he's not the biggest fan of the team (possibly) moving to Los Angeles. Imagine Rivers leaving in free agency and the Chargers not getting a single draft pick in return?

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