Mathias begins his first season with the Ducks and ninth in professional baseball. The infielder spent three seasons at the Major League level, including time with the Milwaukee Brewers (2020, 2022), Texas Rangers (2022), Pittsburgh Pirates (2023) and San Francisco Giants (2023). In 73 MLB games, he compiled a .246 batting average with six home runs, 30 RBIs, 21 runs, 44 hits, eight doubles, seven stolen bases, 19 walks and a .708 OPS. He made his Major League debut on August 4, 2020, against the Chicago White Sox and hit his first big league home run on June 11, 2022, off Washington Nationals pitcher Patrick Corbin.

The California native played the first five seasons of his professional career in the Cleveland Indians organization, peaking at Triple-A. He was named an MiLB.com Organization All-Star in both 2016 and 2018 while also earning Carolina League Post-Season All-Star honors in 2016 with High-A Lynchburg. In his minor league career, the 30-year-old has accrued a .267 batting average, 41 homers, 264 RBIs, 306 runs, 525 hits, 138 doubles, 11 triples, 59 steals, 268 walks, a .364 on-base percentage and a .775 OPS in 563 games. Mathias was originally selected by the Indians in the third round of the 2015 amateur draft from California Polytechnic State University, San Luis Obispo.