Ashcraft will start Sunday's game against the Blue Jays, Charlie Goldsmith of The Cincinnati Enquirer reports.
Connor Overton was initially scheduled to start Sunday's series finale in Toronto, but he was scratched due to back soreness. After Ashcraft's contract was selected by the Reds on Friday, he'll make his first major-league appearance while starting on short notice. The severity of Overton's injury isn't yet clear, but it's possible that Ashcraft remains in the rotation if Overton requires a trip to the injured list. Over seven starts at Triple-A Louisville this year, Ashcraft posted a 2.48 ERA and 1.52 WHIP in 32.2 innings.