[2] Eisert made his professional debut in 2021, splitting the year between the Single–A Dunedin Blue Jays, High–A Vancouver Canadians, and Double–A New Hampshire Fisher Cats.

In 32 relief outings split between the three affiliates, he accumulated a 6–1 record and 3.55 ERA with 82 strikeouts across 63+1⁄3 innings pitched.

[3] Eisert spent the 2022 campaign with the Triple–A Buffalo Bisons, making 45 appearances and recording a 3.41 ERA with 77 strikeouts across 60+2⁄3 innings of work.

[6] On June 17, 2024, Eisert was selected to the 40-man roster and promoted to the major leagues for the first time.

[9][10] On January 23, 2025, Eisert was traded to the Tampa Bay Rays in exchange for cash considerations.