The Stanford men’s basketball team is trying to escape a funk.

Daejon Davis might be just the player to help.

Well, maybe the newest version of Davis.

“I didn’t really see a lot of other areas that were more important (to develop) than my mental toughness,” Davis said at Pac-12 media day. “I think mental toughness is everything for myself, just becoming the leader that I’ve always been thought of and actually becoming that leader for our team.”

The Cardinal have had four straight sub-20-win seasons for the first time since that was the norm for the program from 1942-1986. They have made just one NCAA Tournament appearance (2014) in the past 11 years.

Stanford is projected to finish 10th in the Pac-12 this season, but all of those trends could drastically change if Davis does what those close to him think is possible.

“When he’s at his best offensively and is a complete player, he’s as good as there is,” said head coach Jerod Haase, who is 48-49 (25-29 in the Pac-12) at Stanford. “He can be an all-conference-type player, but what’s hindered him in the past is when times are tough or when adversity hit, it affected him. I think in the offseason, he’s in a position where he understands that, and not only that, has really pushed through and handled adversity well.”

Davis’ production has always been fine. He joined Cal’s Paris Austin as the only players in the conference to rank among the top 30 in scoring and top 10 in assists and steals last season.

But the 6-foot-3 junior also ranked among the top five in turnovers (3.2 per game) and often disappeared because of foul trouble or when games turned lopsided.

Davis spent portions of the offseason meeting with Bay Area business leaders and experts on mental toughness off the court. To help him on the court, Haase brought in prized point guard prospect Tyrell Terry.

A four-star prospect and three-time state champion at Minneapolis’ DeLaSalle High, Terry is a pure point guard who will assume some of the ballhandling responsibilities and allow Davis to play off the ball and showcase his skill set.

“I think his game is going to flourish as he has the stability and on the court mentally, not getting too high or too low,” Haase said. “He’s as dynamic of a person as I’ve ever been around, and when things are good, he can take an entire team with him to really good spots, and when he gets frustrated or struggles, he really takes the team with him some.

“So far, he’s really off to a great start with that stability part, and I think his game, as he gets more and more consistent with handling adversity, I think his game is going to absolutely flourish.”

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It will have to.

Davis, Oscar da Silva and Bryce Wills are the only starters returning on a team that lost KZ Okpala to the NBA and Josh Sharma to graduation. Kodye Pugh has already been ruled out for the season with a knee injury and Trevor Stanback is on a medical hardship year.

In August, the team took a 10-day, three-country European trip, visiting Rome, Florence, Milan and Lake Como, Italy; Lugano, Switzerland; and Munich, Germany. Stanford made similar offseason journeys four other times since 2000 and followed up with a combined 100-37 record in those years.

“The timing was fantastic for the international trip,” Haase said. “It was an opportunity for the guys to get to know each other better and to really work on the cohesiveness of the team and get the guys really buying into just the whole plan that we’re kind of executing right now. The guys were fantastic. From an experience standpoint, they just absolutely loved and ate up every part of the tour, and then from a basketball standpoint, I think we laid a foundation, and I think we’re clear going into the season right now that we know what our road map needs to be.

“Now, we need to coach it and players need to execute that plan to have some success.”

Rusty Simmons is a San Francisco Chronicle staff writer. Email: rsimmons@sfchronicle.com Twitter: atRusty_SFChron