Fien attended Great Oak High School in Temecula, California.[1] In Summer 2024, he played with the USA Baseball's 18U National Team.[2] He also played in the 2024 High School All-American Game where he won the MLB Develops MVP Award.[3]
Texas Rangers
Fien was a top prospect for the 2025 Major League Baseball draft.[4] Fien was selected 12th overall in the first round of the 2025 Major League Baseball draft by the Texas Rangers.[5] He signed with Texas for a $4.8 million signing bonus on July 21, 2025.[6] Fien spent his professional season with the Single-A Hickory Crawdads; in 10 games for the team, he slashed .220/.267/.341 with seven RBI and one stolen base.[7]