Adam Samuel Oller (born October 17, 1994) is an American professional baseball pitcher for the Kia Tigers of the KBO League.

He has previously played in Major League Baseball (MLB) for the Oakland Athletics and Miami Marlins.

As a senior, Oller helped the Crusaders reach the State Championship Game and was named all-state at both pitcher and catcher.

[6] In 2018, Oller split the year between the Low-A West Virginia Power and the High-A Bradenton Marauders, struggling to a 6.29 ERA with 68 strikeouts in 73.0 innings of work across 29 contests between the two teams.

[9] He made 4 appearances (all starts) for Windy City, posting a 2-1 record and stellar 0.67 ERA with 45 strikeouts in 27.0 innings of work.

[10] He spent the remainder of the year with the Single-A Augusta GreenJackets, logging a 5-6 record and 4.02 ERA with 93 strikeouts in 17 starts for the team.

On December 12, 2019, the New York Mets selected Oller in the minor league phase of the Rule 5 Draft.

[21] On November 13, 2023, Oller signed a minor league contract with the Cleveland Guardians that included an invitation to spring training.

[24] In 6 games (3 starts) for the Triple–A Jacksonville Jumbo Shrimp, he compiled a 3–0 record and 2.88 ERA with 24 strikeouts over 25 innings of work.