STANFORD (AP) — The tough and tenacious way Trent Murphy plays football can be traced to his early years growing up just a few miles away from where the outside linebacker will take the field for Stanford against Arizona State in the Pac-12 championship game Saturday night at Sun Devil Stadium.

Murphy, who leads the nation with 13 sacks, grew up in a rural area of Mesa, Ariz. He comes from a large family of large people who raised him to work hard and fight for everything.

“It’s part of his genetic makeup,” said his father, Jerry Murphy, a 6-foot-7, 290-pound contract plumber and cancer survivor who instilled that blue-collar attitude in his oldest son more than anybody. “People that know me say I’m a mean son of a (expletive). My grandfather was a mean sucker. Both my grandparents and my mother and my father were just mean cusses. My wife’s father, he was a mean guy. It just slides down to my son.

“But then, you know what? If there’s a kitten on the side of the road, he’s going to stop and help it. If there’s a bully beating the crap of a kid, he’s going to beat the crap out of the bully. That’s the way he was raised.”

Murphy’s menacing ways — along with his bald head, short beard and pale Dutch skin — have earned him the nickname “Yeti” among his Stanford teammates, after the legendary creature of the Himalayas. Cardinal coach David Shaw has called Murphy “a nasty, physical player who’s in his own category.”

For Murphy’s family, though, he will always just be Trenton — an All-American kid from the Arizona desert who learned the values of hard work and tough love at an early age.

Once, his father dumped a trash can of grass clippings, rotten oranges and dog manure Murphy had just cleaned up all over the yard because he thought his son didn’t do a good enough job. Another time, he took off his shirt and tossed Murphy a stick, telling him to pretend it was a knife and try to stab him. Murphy did as he was told, and his father wrapped his shirt around the stick and snatched it to teach his son how to defend himself.

That served Murphy well when he started taking Taekwondo lessons. Murphy’s first match came at 9 years old and, much to the surprise of his parents, it was full contact.

“Most kids would be afraid of that,” Jerry said. “Trenton went up there, and my wife and I are looking at each other like, ‘This Taekwondo match between 9-year-old kids, they’re actually hitting each other?’ We were like shocked. Trenton’s turn was up. This kid had just knocked two kids out. He went to do a roundhouse kick on Trenton, and Trenton just caught this kid’s foot and knocked the kid out like nothing.”

When he was in middle school, Murphy got involved in team roping with his father, who built a rodeo arena on their property — along with a 1,200-square foot weight room. The family owned horses and also had a 400-pound steer calf that Murphy would grab by the horns and wrestle with “just for fun.”

Jerry and his wife, Laurie, would take the family on fishing and hiking trips in an old Chevy Suburban. The outdoors kept them all in shape, and they encouraged their seven children — now ages 30 to 4 — to participate in sports.

Murphy played organized football in fifth grade, but he stopped because of constant plantar fasciitis. As a freshman at Brophy College Preparatory, an all-boys Jesuit high school in Phoenix, he tried out for the swimming team. He left the pool after a week.

“He came home and said, ‘I can’t wear Speedos,” Laurie Murphy said.

One of Murphy’s three older sisters, Kayli, a 6-foot-2 former Arizona State basketball player in her first year as a graduate assistant for the Sun Devils, tried to help her brother on the hardwood. That turned out to be a lost cause, too.

“He would foul people and hurt people constantly. I’m like, ‘Trent, you’re a football player on the basketball court. You just can’t do it,’” Kayli said.

Murphy, the 2009 Arizona state discus champion, enjoyed the contact of football more than anything. His athletic abilities and determination quickly progressed, and within two years he was being recruited by Arizona State and other major programs.

Former Stanford coach Jim Harbaugh convinced Murphy he’d fit perfectly as a pass-rushing outside linebacker in his 3-4 defense. During his visit to the Murphy household, Harbaugh spent time playing chess on the living room floor with Murphy’s siblings and grabbing milk out of the refrigerator for them to prolong his pitch.

Murphy has since morphed into a 6-foot-6, 291-pound man and likely first-round NFL draft pick for seventh-ranked Stanford (10-2, 7-2 Pac-12). While Mohawk-wearing middle linebacker Shayne Skov has received more publicity nationally, Murphy has been Stanford’s best defensive player the last two years.

Skov and others at Stanford were disappointed Murphy didn’t win Pac-12 Defensive Player of the Year. That honor went to Arizona State (10-2, 8-1) defensive tackle Will Sutton this week.

“His work ethic and his approach is the most resonating thing on this defense from a leadership perspective,” Skov said. “I think it’s sad to a degree, kind of tragic he’s gone so unnoticed. The guy has dominated.”

Perhaps the toughest obstacle Murphy had to overcome came off the field last December.

After the Cardinal won the Pac-12 title game over UCLA, Murphy learned his father had kept devastating news from him since October because he didn’t want it to affect his play or his decision to turn pro. Jerry had lung cancer, which also had taken the life of Murphy’s grandmother a year earlier.

Jerry had surgery Dec. 13 to remove his right lung. He has been cancer free since.

Trent flew home before Stanford’s preparation for the Rose Bowl. He helped with chores around the house, including cleaning his father’s office, fearing Jerry could be more susceptible to infection following surgery.

Before his father was fully recovered, agents were calling the house hoping Murphy would declare for the NFL. The draft advisory board projected Murphy to be selected in the second or third round, Jerry said.

Following the advice of his father, Trent returned to Stanford as a fifth-year senior. He has finished his bachelor’s degree in science, technology and society and earned a minor in political science this fall.

Murphy’s parents couldn’t watch Stanford’s victory over Wisconsin in Pasadena last season while Jerry recovered, and that only serves as more motivation for Murphy to lead his team back there this New Year’s Day.

No matter what happens in the Pac-12 title game, it promises to be a special night for Murphy’s family. There will be at least 40 family members, including his father, at Sun Devil Stadium on Saturday night.

Murphy, who used to race his sisters up A Mountain next to the stadium, has never played a collegiate game at Arizona State. He missed Stanford’s last trip to Sun Devil Stadium in 2010 because he had a broken foot, and it has been his dream to play there — and his family’s dream to watch him there.

Now they’ll finally get the chance.

“Sometimes you just have to pinch yourself and say, ‘Wow,’” Laurie Murphy said. “Life is good. Life is good in the Murphy household right now.”