[3] He made his professional debut in 2015 with the Low–A Batavia Muckdogs, the Single–A Greensboro Grasshoppers, and the High–A Jupiter Hammerheads, accumulating a 0–3 record with a 6.26 ERA in 26 innings.

[3] His 2018 season was split between Jupiter, the Double–A Jacksonville Jumbo Shrimp, and the Triple–A New Orleans Baby Cakes, accumulating a 2–4 record with a 3.08 ERA in 52.2 innings.

[5] He made his major league debut on August 4, striking out one batter over 1+2⁄3 innings pitched.

[8] Keller only made two appearances for the Angels in 2020, giving up two runs in 2+1⁄3 innings for a 7.71 ERA with a lone strikeout.

He made 52 appearances out of the bullpen for Yomiuri in 2024, compiling a 2–2 record and 1.53 ERA with 54 strikeouts across 47 innings pitched.