Sauer was selected by the Royals in the Rule 5 Draft on Wednesday, Chris Kirschner of The Athletic reports.
Sauer, 24, posted a 3.42 ERA and 83:29 K:BB over 68.1 innings at Double-A Somerset in 2023. The right-hander pitched in relief in the Arizona Fall League and it's not clear whether the Royals plan to use him as a starter or reliever.