Since joining the league, the 5-11, 215-pound running back has appeared in 75 games (19 starts), after being selected by the Vikings in the third round (102nd overall) of the 2019 NFL Draft. With 2,370 running yards and 11 rushing touchdowns on 584 carries (4.1 average), as well as 817 receiving yards and six receiving touchdowns on 100 receptions (7.2 average), Mattison has amassed 3,088 career yards from scrimmage.

Mattison, a product of San Bernardino, California, attended Boise State University for three seasons (2016–18). In 40 career games, he accumulated 2,829 running yards and 33 rushing touchdowns on 581 carries (4.9 average) in addition to 60 receptions for 511 yards and one touchdown. In 2018, Mattison, a senior, made history by becoming the first player from Boise State to win the Mountain West rushing title. He led the conference, finished ninth in the country with 1,415 running yards, and seventh with 17 rushing touchdowns.

According to NFL insider Jordan Schultz, former Minnesota Vikings running back Alexander Mattison has agreed to a free-agent contract with the Las Vegas Raiders. Mattison was told by the Vikings that he would be free in February. He had played in Minnesota for the first five seasons of his career.

The Vikings selected Mattison, a Boise State product, in the third round of the 2019 draft. Having been Dalvin Cook’s backup for the first four seasons of his career, he took over as the starting quarterback in 2023 when Cook was cut before the season began.