The Diamondbacks optioned Solomon to Triple-A Reno following Tuesday's 6-4 loss to the Rangers.
Solomon wasn't needed in relief Tuesday, but he'll lose his spot on the 26-man active roster in any case after the Diamondbacks promoted right-hander Brandon Pfaadt from Triple-A in a corresponding move in advance of his scheduled start in Wednesday's series finale in Texas. During the three-plus weeks he was up with the big club, Solomon made five relief appearances and was blitzed for 18 earned runs on 17 hits and 11 walks over 13.1 innings.