Sandoval was promoted to Triple-A Salt Lake on Friday, Fabian Ardaya of The Athletic reports.
Sandoval had a 2.06 ERA, 0.96 WHIP and 145:29 K:BB over 122.1 innings last season as he worked his way from Low-A to the Double-A level by the end of the season. The 22-year-old had a 3.60 ERA and 1.05 WHIP across 20 innings at Double-A Mobile this season and has been a fast-rising prospect for the Angels since being acquired from the Astros for Martin Maldonado last July.