Doyle was optioned to Triple-A Albuquerque on Friday.
The 24-year-old finished last season on the big-league roster while giving up six earned runs over 2.1 innings, and he'll open 2021 in the minors. Doyle will skip Double-A after posting a 3.25 ERA, 1.03 WHIP and 48:13 K:BB over 36 innings at High-A in 2019.