Alexander Mattison is the new leader in the Vikings backfield.

His long-awaited promotion became official Friday when the Vikings released running back Dalvin Cook, Mattison's close friend whom he followed in practices and games for four seasons. Now Mattison is the unquestioned starter, bringing more playing time at a stage in his career — he turns 25 on June 19 — where he's naturally feeling more comfortable.

"Just coming in with the confidence of being a seasoned vet now — sounds weird to say," Mattison said after a spring practice last month.

The Vikings turn to Mattison as head coach Kevin O'Connell wants a more efficient running game. The 5-11, 215-pound back is capable of running through and hurdling over defenders, but he has lacked Cook's breakaway speed. That might not be a big deal for O'Connell, who has lamented last year's 1- and 2-yard gains. The Vikings also boast a passing game with game breakers from Justin Jefferson to T.J. Hockenson.

While a better run game doesn't necessarily mean more handoffs — the Vikings ranked 27th in rushing attempts last season — O'Connell has said he also sees Mattison as a "three-down" starter with chops as a receiver and pass blocker. How the pecking order unfolds behind Mattison remains to be seen.

"It's been really good to see Alex Mattison take a few more reps and really show that all three-down kind of ownership that he's been capable of for a long time," O'Connell said during offseason workouts. "Between Kene [Nwangwu] and Ty [Chandler], there already seems to be a really nice competition brewing there, because both of those guys are having really solid springs."

The rest of the Vikings runners offer rawer talent. Minnesota's reserves combine for 28 NFL carries among Nwangwu, the dynamic kick returner; Chandler; and rookie DeWayne McBride, a seventh-round pick.

Nwangwu has the home-run speed. He leads the NFL with three kickoffs returned for touchdowns since he was drafted in 2021's fourth round. But his playing time has been limited to 22 carries for 75 rushing yards during two regular seasons.

"It's just consistency," Nwangwu said. "Being a consistent player coaches can count on."

Chandler, a 2022 fifth-round pick, is a month older than Mattison, who played just three seasons at Boise State. He didn't play much as a rookie, taking six carries over three games in a year interrupted by a broken thumb. But Chandler's quick feet and shiftiness flashed in the preseason when he gained 113 yards and a touchdown on 15 attempts.

"Last preseason, you saw a ton of natural instincts as a runner show up: toughness, great finish," O'Connell said. "We've seen his impact in the pass game and kind of his overall football IQ show up from day one."

There's maybe just one area in which the Vikings offense succeeded running the ball during O'Connell's first season. Pre-snap motions and movement helped create space for 18 rushing touchdowns, which tied for seventh in 2022.

The Vikings otherwise ranked 27th in rushing yardage, 26th in yards per carry and 31st in big runs (20-plus yards). Players being more comfortable in O'Connell's second Vikings season might help, but the team also paid $7 million per season in free agency for blocking tight end Josh Oliver — and changed the leading runner.

"We all knew that was an area of improvement we needed," Mattison said. "Coming into this year, there's more emphasis. ... [With] a year of foundation we have, we can look back, look what we can correct, look at what we do well; improve. Yeah, it's definitely more of an emphasis and it's looking good."