Medlen was scratched from his scheduled start at Triple-A Reno on Monday, an indication he could be summoned to the big leagues when the Diamondbacks require a fifth starter Friday against the Astros, Steve Gilbert of MLB.com reports.

EDGE Analysis

With Robbie Ray landing on the 10-day disabled list Monday with a Grade 2 oblique strain and expected to miss multiple turns through the rotation, the Diamondbacks will delve into their minor-league ranks to find a replacement starter. Neither of the Triple-A starters on the 40-man roster (Braden Shipley and Troy Scribner) have been particularly good this season, so it appears the Diamondbacks will instead look to Medlen, who attended spring training as a non-roster invitee, to fill the rotation void. Medlen hasn't dazzled at Reno either with a 6.00 ERA and 1.50 WHIP, but he's at least struck out a batter per inning and has enjoyed some prior success at the big-league level, although not in about five years. Arizona can easily clear a spot for Medlen on the 40-man roster by transferring Taijuan Walker (elbow) to the 60-day disabled list, so expect a transaction to become official prior to Friday's series opener.