Zuber was used as a swingman as a sophomore and junior at Arkansas State before he moved to the bullpen full-time and dominated in 2017, when the Royals took him in the sixth round. He continued to improve in that role during his first two professional seasons before breaking out in earnest at Class A Advanced Wilmington, where he was a midseason All-Star, and Double-A Northwest Arkansas in 2019. He saved 21 games between the two stops, recording a 1.79 ERA and 11.1 K/9 over 55 1/3 innings (43 appearances). The Royals sent Zuber to the Dominican Winter League for some extra work, and he responded with a 1.80 ERA and 18 strikeouts in 15 innings.
Zuber may be an undersized right-hander, but he has a surprisingly big fastball that he can back up with a pair of quality secondary pitches. He typically sits at 94-95 mph out of the bullpen but can reach back for a few extra ticks as needed, throwing his heater with late life that allows him to beat hitters inside and above the zone. Scouts prefer his curveball, an above-average pitch, to his slider, though the latter also is at least average. Opposing hitters struggle to square up Zuber and batted just .181 with a .522 OPS and 14 percent swinging-strike rate against him in 2019.
As a smaller right-handed pitcher with late-inning potential, Zuber earns comparisons to former Royals closer Greg Holland. The Royals plan to give him a long look in big league camp during Spring Training after his stellar 2019 campaign.