FRISCO, Texas -- Almost every time Dallas Cowboys coach Jason Garrett talks about tight end Jason Witten, the message is the same.

"He's as professional a person, as professional a player as I've ever been around," Garrett said last season. "His commitment to doing things the right way, his commitment to excellence is unmatched. Again, it's beyond just a day, it's everything he does within that day."

With Witten signing a four-year extension through 2021, according to league sources, he is again showing what he is about.

This deal doesn't add any guaranteed money to his pockets. As the franchise leader in receptions and just 17 yards away from being the leader in yards, he could have waited on a new deal with more guaranteed money in the future. He could have waited to test the market in 2018, even as a 15-year veteran, to potentially chase a Super Bowl ring with another team.

With his résumé, he could have demanded more than he received.

But Witten's intention is clear. If he is going to win a Super Bowl, it will be with the Cowboys. He is doing what Garrett says he does -- pouring his heart into this team.

Witten is the soul of these Cowboys. Going into the last year of his deal, it would have been difficult for him to lead the way he has without the security of added years, if not added money. He did not want teammates to wonder where he would be after the 2017 season. He did not want to incessantly answer questions as to whether this will be his final year with the Cowboys.

He took care of that by taking care of the Cowboys.

The Cowboys have the right to restructure his $7.4 million base salary this year to create nearly $4 million in room. The money can come in handy if the Cowboys have the opportunity to acquire a difference-maker in a trade later this offseason or even during the season.

Witten's cap numbers in the future are manageable and will allow the Cowboys to keep their younger talent when they come up on contract years.

As much as this can help the Cowboys' salary cap in 2017 and beyond, it's more than that.

Witten arrived in Dallas as a 21-year-old kid full of optimism. He is now a 34-year-old father of four. He has become the franchise leader in a number of categories and will add more in 2017, but he is also the conscience of the locker room.

Last season, he perfectly handled the personal disappointment of seeing Tony Romo get injured -- and ultimately lose his job -- while also supporting Dak Prescott. Witten has the gravitas to handle any situation in the locker room, on either side of the ball, with veteran players and younger players.

A little more than a dozen players were part of the council that created the much-lauded players' creed last season, but Witten led the discussions. If players become upset with different situations, Witten can calm the waters. He bridges the concerns of players to coaches and coaches to players.

As he stood in the locker room after the loss to the Green Bay Packers in the divisional round, Witten was emotional as he answered questions. He realized his chances to get to that Super Bowl were dwindling. Retirement became a real option for the first time.

Now, that will have to wait.

As the informal captains practices go on at The Star, the Cowboys' training facility, Witten is there every morning, running and lifting and serving as the example for every other Cowboy to follow.

Once again, he's all-in.