Both sides have been trying to negotiate a long term contract to keep Cook with the Titans. It's likely that Cook wants a bigger deal and the Titans are cautious to give him one, given that he's performed below expectations since coming into the league.
Cook caught just 44 passes for 523 yards and four touchdowns in 2012. The previous season, he had 759 receiving yards off of 49 receptions. He hasn't bested either of those numbers in any of his four years in the NFL.
One possibility is that the Titans could use the franchise tag on Cook. The deadline to do so is 4 p.m. ET on Monday. Unfortunately for the Titans, it's likely going to be a difficult process, even if they use the tag, as Cook plans to dispute how the tag is being used on him.
As explained by Wyatt here, Cook plans to challenge whether or not he should be qualified as a tight end under the tag. He thinks, due to the way that he's been used in Tennessee, that he should be designated as a wide receiver. The difference between the two tags is about $4.5 million in pay, so it's definitely something to keep an eye on going forward.
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