Arrighetti will start Sunday's game in Kansas City, Mitch Bannon of The Athletic reports.
The Blue Jays had been considering deploying Arrighetti behind an opener for a second straight turn through the rotation, but the team now appears set to use the right-hander as a traditional starter in the series finale. Arrighetti has struggled to a 6.55 ERA and 1.36 WHIP with a 10:5 K:BB over 11 innings across three starts with Toronto, and he hasn't thrown more than 79 pitches in any of those outings.