Marcus Allen is homebound. Sin City. Senior year.

It’s Monday afternoon and he's on a bus with his twin brother, Malcolm, and the rest of his Stanford Cardinal teammates. Soon it’ll be wheels up from the Bay Area and down to the desert, where the Arizona State Sun Devils await in the first round of the Pac-12 Men’s Basketball Tournament, Wednesday (Noon PT / 1 p.m. MT on Pac-12 Network).

Something of a full circle for Allen. He caught the eye of former Cardinal coach Johnny Dawkins as a Centennial High Bulldog, the gym just a 20-minute drive from The Strip. The Brothers Allen racked up straight A’s in the classroom and led Centennial to the state title game their senior year in 2013, but fell short in the finale.

Now Marcus’ collegiate chapter is coming to a close, with No. 9 seed Stanford (14-16 overall, 6-12 Pac-12) aiming to snap a three-game losing streak and make a darkhorse run.

“It’s bittersweet,” Allen said. “I’m going to play in front of my family and friends, and at a time like this when you get a chance to do something special, it’s huge. I’m just very excited and to play in the new arena in Vegas is huge, I’m excited.”

Early in his Cardinal career, Allen developed a reputation as a high-energy playmaker with all-up-in-your-grill defense. Now he’s also become the most tenured player on the roster with 127 games played entering the Pac-12 Tourney.

Allen has turned down the shot volume and turned up the efficiency, scoring 8 points per game on 43 percent shooting compared to 11.1 points on 40.9 percent last year. He loves to throw down menacing dunks and can often be seen stealing the ball and taking it to the other hoop by his lonesome. And fast.

Though they might have been born on the same day, the Allen twins didn’t get to share the Senior Day experience together this season. Malcolm redshirted his sophomore 2014-15 season after missing early action recovering from a broken wrist.

While Malcolm has the opportunity to return to the Cardinal for a fifth season, this tournament is all she wrote in the Pac-12 chapter of Marcus’ playing career.

“It’s been huge,” Allen said of playing alongside his twin. “It’s a great experience to spend the past four years playing basketball and have someone to push you to get better, someone to push you in check. It’s been a blessing. I wouldn’t change the past four years for the world.”

So proud of my brother @MarcusAllen_15 for being named to the Pac-12 All Defensive team.. well deserved and better things on the way

— Malcolm (@MalcolmAllen03) March 7, 2017

The Allen family roots with the Trees run deep.

The twins’ mother, Trina Wiggins, competed with Stanford gymnastics and graduated in the class of ’82, before becoming a pediatrician and fitness competitor. To this day, Wiggins still mentors current Cardinal gymnasts and competes in elite fitness events.

“When I was growing up, I would come with my mom to alumni events and things of that nature, we’d throw parties at our house,” Allen said. “So I came with her for her 20th reunion. I kind of grew up around Stanford and my mom didn’t make me [enroll at Stanford] or persuade me, per se. When the time came, I made the decision. She comes to every game. She’s still very involved. I love it.”

You can bet she’ll be there on Wednesday for the noon marquee matchup against No. 8 seed ASU (14-17, 7-11). The last time these two teams met on Feb. 11 in Tempe, Allen set season highs with 20 points and 7 rebounds.

“ASU’s a great team,” Allen said. “They have a good shooter in Torian Graham and a good point guard in Tra Holder. We’ve got to try to contain them and we’ve got to dig in defensively. That’s the game plan.”