HOUSTON -- J.J. Watt is the highest-paid defensive player in the NFL. He'll make $16.6 million a year with an extension that locks him in with the Houston Texans through the 2021 season, and he's earned every penny.

The agreement on the six-year deal could pay him $100 million, league sources told ESPN's Chris Mortensen. It includes $51.8 million guaranteed, the most for a defensive player in NFL history.

Watt and the Texans reached a deal before anything ever got ugly, before real concerns about his worth and value to the Texans arose. Watt expressed some frustrations publicly last month, but maintained that nothing had reached the point to which he would have to get involved in his negotiations. The player getting involved could have meant a holdout, one during which Watt would have had more leverage than any non-quarterback in the NFL.

He's earned this with a 2012 campaign (20.5 sacks) that made him the defensive player of the year. He's earned it with a 2013 season that was just as dominant, if not one that included the same numbers (10.5 sacks). He's earned it by being exactly the player off the field that the Texans want representing them.

Some think the Texans held all the leverage here. They had Watt for another two years on his rookie contract and could have franchised him for two more, trapping him in Houston for four seasons of underpaid labor.

The reality is Watt had leverage he never used. He never had to.

Had he held out, the Texans would have caved. Watt isn't replaceable. In that way, he is more like an elite quarterback than any other player. He's an elite pass-rusher, who changes the way opponents operate. He has been the most dominant player at his position for two seasons, and by far the most dominant player on the Texans' roster for that long. The Texans would not have risked going into the 2014 season -- or any season for that matter -- without arguably the league's best defensive player.

Over and over again, Watt has said he hopes he gets to stay in Houston for a very long time.

The clock resets with this deal -- it will tick for six extra years.