PHILADELPHIA -- Some things don't change, even after 15 years. Jason Witten didn't wear sleeves in the frigid conditions Sunday at Lincoln Financial Field. The veteran tight end also mostly shunned huddling under a heavy coat on the sidelines.

Witten can still find motivation and promise in a miserable, cold win like Dallas' underwhelming 6-0 season-ender over the Eagles, yet another reason he vows he'll be back for his 16th season.

"I've never wore sleeves," Witten said Sunday. "There's been some cold games. It was definitely chilly out there. The weather was ugly. You know, the mind is a powerful thing. ... That's part of a little bit of the old-school in me.

Last time in 2017. pic.twitter.com/MmrfGLgIAb — Kate Hairopoulos (@khairopoulos) December 31, 2017

"I know this -- my burn is strong inside me to play at a high level and to be a part of this group of guys and be a leader and see this thing through and go compete for a championship. When I wake up tomorrow that's what my focus will be on."

The Cowboys avoided another dreaded 8-8 finish, going 9-7, but the drop-off from 13-3 in 2016 to missing the playoffs leaves Dallas disappointed and starting over yet again.

"It hurts because you don't get a whole lot more opportunities at this," said Witten, who was emotional the week before when Seattle ended the Cowboys' hopes of making the postseason. "You don't get a lot of chances at it, and I realize that. Rest assured I'm going to do everything in my power to help us be better as we move forward. It needs to be clear that starts with yourself."

Witten had two catches for 17 yards against the Eagles. He finished the season with 63 catches for 560 yards and five touchdowns. The receiving total is by far his lowest since his rookie season in 2003. His 8.9 yards per catch is the lowest average of his career. He's of course also a key part of the blocking scheme. He played almost every offensive snap this season.

Witten, who turns 36 in May, is the unquestioned team leader and who the team turns to in the locker room. But that doesn't allow for a diminished version of himself on the field. The entire offense underperformed this season.

"I'm as motivated now as I've ever been to play this position at a high level," Witten said, "and help my team in all situations as a leader, as a veteran, but most importantly as a tight end and what that position consists of in this offense. With that, we got to get back to work, evaluate it, strip it down to the most simple form."

Leading up to the Eagles game, he referenced a quote from the movie Bull Durham, the baseball flick that was made before many of his current teammates were born. "Until you win 20 in the show," one of the characters says, driving home the need to keep proving oneself.

Jason Witten: Oh, I’m coming back. I love playing this game too much and I know I can play at a high level. — Kate Hairopoulos (@khairopoulos) December 31, 2017

That's what Witten's done. He's set an array of franchise records, including games played and started. But he's played in the postseason six times and has yet to advance to the NFC championship game or Super Bowl. He doesn't want to reduce his motivation to keep playing to reaching that next level, but it is part of what keeps him planning to come back for Season 16.

"It doesn't always happen that way when you get these fairy tales," he said. "I understand that, and that's why I try not to make it about that, more about what I can do to help get us there. With that passion and drive I still have, I think that's why I make the decision that I want to be a part of this group."