TEMPE, Ariz. -- Larry Zierlein woke up on a Saturday morning in April 2013, two months after he was hired by the Arizona Cardinals for the final chapter of his coaching career, and had nothing to do.

Instead of wasting his weekend bumming around Phoenix, Zierlein drove two hours north to Sedona, then down a two-lane highway to Jerome.

That road trip began a love affair for Zierlein with Arizona and its neighboring states.

Two years later, Zierlein has visited more than 10 cities and national parks throughout Arizona and Utah, mostly during offseason weekends. Zierlein, the Cardinals' assistant offensive line coach who turned 70 on Sunday, has become a road-trip fanatic.

He’s been to Monument Valley, the Grand Canyon, Flagstaff, Canyon de Chelly National Monument, Bisbee, Tubac in Arizona and to Zion, Bryce, Canyonlands and Arches national parks in Utah.

“That’s something I like to do a lot of,” Zierlein said.

Zierlein wasn’t supposed to be within driving distance of these geological wonders. He wasn’t supposed to be preparing for his 43rd year as a football coach, a career that started as an eighth-grade coach in rural Texas and now has him living in a Residence Inn during the season, where he wakes up at 4:45 a.m. with a hot breakfast waiting for him in the lobby and a freshly made bed and clean towels awaiting his return.

If you look around the league, he wasn’t even supposed to be coaching at all at this point. He’s among a small handful of NFL assistants who are 70 or older. There are at least seven, according to an informal poll by ESPN. The Cardinals have three of them.

Zierlien was supposed to be enjoying the fifth year of his retirement at the home he built in Texas with his wife, Marcia. But as Zierlein has learned over the past eight decades, life doesn’t always pan out the way you planned.

There was a period in the early 1980s where being a head coach -- with all the glitz and glamour that came with it -- was atop Zierlein’s list of goals he hand-wrote and read every day. As an assistant at the University of Houston, he was offered head college jobs but held out to be Bill Yeoman’s replacement with the Cougars, according to his son, Lance. But after Yeoman’s staff was fired, Zierlein reflected on his goals and decided being a head coach wasn’t all it was cracked up to be.

At 55, after 28 years in high school and college, Zierlein decided he wanted to coach in the NFL.

This will be his 15th NFL season and looking back with a life’s worth of wisdom, Zierlein wouldn’t have wanted his path to have gone any other way. His career not only took him from the upper echelon of Texas high school, NCAA and NFL football, but it led Zierlein to the UFL, Arena Football League and World League of American Football.

The first phone call took place in late January 2013, just a few weeks after Bruce Arians was hired as the Cardinals’ new coach. Offensive coordinator Harold Goodwin was looking for a recommendation for a new assistant line coach and he turned to Zierlein, whom Goodwin worked under as a quality control assistant in Pittsburgh, for advice. The more they talked, the more Goodwin knew Zierlein was the right fit -- but he didn’t know Zierlein was ready to coach again.

The first year of Zierlein’s “retirement” after the Steelers fired him in 2010 was productive. He stayed busy, selling his homes in Pittsburgh and Buffalo while building his home in Texas. He drove to Houston to watch his son, Michael, coach. He’d go to local high school and Texas State games.

“It was good,” he said. “There weren’t any problems.”

He was 65, the age Zierlein always thought he’d retire at. Everything was weirdly fitting into place. He had time to see his three kids and nine grandchildren. But as the year passed, retirement and Zierlein didn’t get along. Zierlein’s son, Lance, knew his father didn’t want to end his career by getting fired -- the first time Larry had lost a job aside from a coaching change.

“I think it really left a bad taste in his mouth,” said Lance, a sports radio host in Houston and draft analyst for NFL.com. “I think this has been great closure for him. He’s still enjoying it. Quite frankly, he’s enjoying coaching more than any time I’ve seen him right now.”

After Arians signed off on hiring Zierlein (the two worked together in Cleveland and Pittsburgh), Goodwin’s second call to Zierlein that night lasted about five minutes -- most of which were spent buttering Zierlein up before popping the question.

“This situation out here is so good,” Zierlein said. “I’m the assistant now, which makes it where I tell Goody, ‘If we give up eight sacks a game, it’s his fault. If we don’t give up any, it’s because he’s got good help.

“I’m really, really glad I got back in.”

Arizona is a long way from the wheat and cattle farm Zierlein grew up on about seven miles northwest of Lenora, Kansas.

His hometown had 300 people in it. He graduated high school with 17 others in his class. He played 11-man football for a school that had no more than 45 boys.

“It was Mark Twain kind of stuff,” he said.

Life took Zierlein from Lenora to three colleges, broken up by a two-year stint in Vietnam as a Marine. Chronic dislocated shoulders ended his playing career at Fort Hays State and led Zierlein into coaching.

His road to the NFL took longer than most. He came home from Vietnam at 22, married Marcia at 24, was hired for his first head job -- coaching eighth graders in Abernathy, Texas -- at 27, moved up to the University of Houston at 32, then onto the Cleveland Browns at 55.

But age has become just a number to Zierlein.

“When you’re younger, you look at people this age and you say, ‘Oh, that’s old,’” Zierlein said. “And then you get to this age and you say, ‘It’s not.’"

Lance thinks every year is his dad’s last, but Larry doesn’t know how much longer he’ll keep coaching. He has three criteria that’ll help him decide every year: No. 1, “That they still want me around,” No. 2, “If I feel like I’m contributing and not just taking up space,” and No. 3, “If I’m enjoying it.”

“If any one of those things are absent, then that’ll be it,” Zierlein said.

“There’s going to come a point, probably, if they don’t tell me to go or I don’t quit enjoying it, that it’s time to go. When that happens that’ll be it.”