The Astros promoted Diaz from Double-A Corpus Christi to Triple-A Sugar Land on Tuesday, Chandler Rome of the Houston Chronicle reports.
Diaz makes the jump to Triple-A after slashing .316/.367/.504 with nine home runs and 48 RBI across 267 plate appearances at Corpus Christi. At Sugar Land, he'll be part of a catching group that includes one of the Astros' other top prospects in Korey Lee. Since Diaz also made starts at first base as well as the corner-outfield spots during his time at Corpus Christi, Lee still appears likely to see most of the work behind the plate.