FRISCO, Texas -- Ed "Too Tall" Jones was walking through Dallas/Fort Worth International Airport in February when he got the word.

"Jason Witten's coming back," somebody told Jones, the former Dallas Cowboys defensive end.

"Oh, thanks," the man known to many as "Too Tall" said. "He's coming back to coach?"

"No," he was told as he strolled through the concourse to baggage claim. "He's coming back as a player."

Jones almost stopped in his tracks.

Witten spent 2018 with ESPN's Monday Night Football. He had his retirement news conference. He was 36 years old and his legacy was secure as one of the greatest tight ends in NFL history.

"Now that shocked me," Jones said. "That was a surprise."

Forty years ago, Jones shocked everybody when he walked away from football.

Unlike Witten, Jones was in his prime. He was 28, five years into his career and a Super Bowl champion. In June 1979, Jones called Gil Brandt, the Cowboys' personnel chief, and set up a meeting at Brandt's house, which was within a couple of blocks of where coach Tom Landry and general manager Tex Schramm lived.

"'We're going to retire. We're going to go into boxing,'" Brandt remembered Jones saying. "And I said, 'You know, we've got a chance to be a Super Bowl team again. You're extremely important to us. Is it about money?' and he said, 'No, we just want to go into boxing.'"

Growing up in Jackson, Tennessee, boxing was Jones' first love. He was an outstanding basketball player, too. He did not focus on football until he got to Tennessee State. But boxing had his heart.

"I did something I wanted to do all my life," Jones said. "I knew I'd do it one day, and I was happy because I never wanted to looked back when I was 40 or 50 and not experience it. Football was always No. 2. Boxing was No. 1. So that was a relief."

Teammates knew of Jones' love for boxing, but were surprised when the news broke. Cliff Harris, a Cowboys Ring of Honor safety, called Jones' departure "mysterious." Ring of Honor receiver Drew Pearson was in Pennsylvania, driving home to New Jersey, when he heard the news on the radio.

"I almost had to pull over because I was stunned by it," Pearson said. "I didn't think he'd do it. I didn't know if he would start another career while this career, the football career, was going so well. He was a bad man playing football."

The Cowboys took Jones with the No. 1 overall pick in the 1974 draft. He was not a full-time player his first few seasons and Landry openly wondered how much he liked football, but there were always spurts of dominance. During the Cowboys' run to winning Super Bowl XII in 1977, Jones had 23 tackles, two sacks, two pass deflections and forced two fumbles.

After the loss in Super Bowl XIII to the Pittsburgh Steelers, he had followed through on a promise he made to himself a season before to return to boxing.

The Cowboys remained supportive of Jones, and teammates showed up to sparring sessions. Pearson remembers the Cowboys flying early to New York so they could see one of Jones' fights on television.

"I don't know where they got it from or whose idea it was, but I received a box from the Cowboys that had a sweatsuit for me to jog in and other stuff with the biggest Cowboys logo I ever seen," Jones said.

Jones had six bouts and won them all, including five by knockout, but he was not considered a true heavyweight contender to challenge Larry Holmes, who was a good friend and encouraged him to get into the ring.

He made more money in boxing -- reportedly $225,000 -- than for the Cowboys in 1978 (reportedly $185,000), but after 10 months he decided to return to football. He never gave a reason why. Some theorized it was the stress boxing put on his mother, but to this day Jones won't divulge why.

"If there's a quote from me about it, I never said it," Jones said. "I never told anybody but family and that's something I can't wait to someday share with the public, to tell you the truth, but all I can say is it was out of my control. But I'm at peace with it. I had accomplished what I wanted to accomplish. And I was successful at it. That's all that really mattered."

Upon his return to football, he studied more film, looking for ways to improve. He took the game more seriously. He boxed at 235 pounds but played at 270 pounds. Putting that weight back on was difficult, but when he put his hand on the ground, he noticed a difference. The miles he ran to prepare for bouts helped his conditioning. His hands were quicker from his rounds sparring. His hand-eye coordination was better. His footwork was refined because of his work inside the ring.

"My reaction time was so much quicker coming off the ball," Jones said. "In that Flex defense, oftentimes I was like 2½ yards off the ball and you had to key two people. Well, when they made their moves, that gave me my keys and I was just a lot quicker. I was able to make a lot more plays."

He started to live up to the expectations the Cowboys had for him as a top draft pick. He played another 10 seasons upon his return, including Landry's final season (1988) and coach Jimmy Johnson's first.

Before Witten played in Sunday's season opener against the New York Giants, Jones shared the mark for longest service in franchise history at 15 years with Bill Bates, Mark Tuinei and Witten. Jones is second to Witten (240) in games played (224) and games started (203).

Jones, who played in three Pro Bowls, is fourth in Cowboys history with 106 sacks. Only DeMarcus Ware (117), Harvey Martin (114) and Hall of Famer Randy White (111) have more.

"Ed Jones is a phenomenal athlete," Brandt said. "He's really bright. He's a guy that belongs in the Ring of Honor. He belongs in the Hall of Fame."

Jones called the 10 years he played after his return "the best 10 in my life." Witten is just one game into a return that could last one season.

"Looking at Jason Witten, what he's doing now doesn't surprise me at all. I said it when he retired that Jason could still play a little longer if he wanted to. Mentally, you've got to want to do it. Football is not an easy sport. People watch you on Sunday and think you make it look easy. They have no idea what you go through. But Jason always appeared to keep himself in great shape. He's never had those big injuries, which is good.

"Taking a year off may be the best thing for him. Now I'm not saying he's got another three or four years, but this year, next year, you'll see someone who's very motivated."