[4][5][6] In 2017, Lowther set a Xavier single-season record with 123 strikeouts and was named to the All-Big East Conference team.

[15] During the 2019 season, Lowther played for the Bowie Baysox of the Double–A Eastern League,[16] going 13–7 with a 2.55 ERA over 26 starts, striking out 154 batters over 148 innings.

[17] Lowther did not play in a game in 2020 due to the cancellation of the Minor League Baseball season because of the COVID-19 pandemic.

[20] He made his MLB debut that day against the Oakland Athletics, pitching a scoreless ninth inning.

Lowther made 1 appearance with the Orioles, pitching 5.1 innings with 5 earned runs, and was designated for assignment on June 15 following the claiming of Jonathan Araúz.

Lowther missed the start of the 2023 season due to injury, and began a rehab assignment with the rookie–level Florida Complex League Orioles in June.

On January 15, 2025, Lowther signed with the Wei Chuan Dragons of the Chinese Professional Baseball League.