Silseth was selected in the 11th round of the 2021 Major League Baseball draft by the Angels and signed with the team, forgoing his senior year of college.

After signing with the team he was assigned to the Arizona Complex League Angels before being promoted to the Double-A Rocket City Trash Pandas.

[7] Silseth returned to the Trash Pandas to start the 2022 season and was named the Southern League Pitcher of the Month for April.

[10] He made his major league debut that night against the Oakland Athletics, pitching six scoreless innings while striking out four batters.

[11] Silseth made seven starts for the Angels in his rookie campaign, posting a 1-3 record and 6.59 earned run average (ERA) with 24 strikeouts in 28.2 innings pitched.

Silseth began incorporating a cutter the next year in spring training, but struggled and was optioned to the Triple-A Salt Lake Bees to begin the 2023 season.

[13] On August 26, Silseth was struck in the head by a thrown ball from Trey Cabbage while running to back up third base in the fourth inning of a game against the New York Mets.