The franchise tag is a useful tool on both the player and franchise levels. On the one hand, at the least, the player is guaranteed a nice sum of money for their services next year. And on the other, the franchise retains a player they feel comfortable handing large sums of money to. But as we've seen firsthand as recently as last season, the tag can be an extension of time to reach a long-term commitment with a player just as easily.
And such is the case with Henry Melton. The franchise tag guarantees a Pro-Bowl defensive tackle 8.45 million dollars, which is clearly not an insignificant chunk of cash. But players also like whatever passes for "long-term security" in the NFL - essentially, even more money up front, but spread over multiple seasons, which helps the franchise.
Melton's tag hinders the team short-term - they have to account for the tag while there's no long-term deal on the table, which might make it more difficult to sign free agents - but that money isn't "permanent" by any stretch, just "accounted for." And if a deal is reached, well, the cap hit just becomes whatever the new deal would be. So, 8.45 million is the most Melton's cap hit in 2013 would be.
What the tag also offers is the certainty that Melton will be a Bear in 2013. It's exclusive - no other team can talk to him, which is huge from the Bears' perspective. Dealing player-to-one-team is far different than that player testing the market with a massive bidding war - it becomes perceived player value versus the single team's value, instead of the player becoming a mercenary with teams bidding for his services. In short, it keeps the player's value down for the franchise.
Ultimately, what the tag sets up is a scenario where the Bears eventually sign a pretty good defensive tackle at a maximum cap hit of the franchise tag. We'll see what happens, but this is just a step in the process, one that lets the Bears keep a player they really like.