Arrighetti will start Wednesday against the Cubs, Chandler Rome of The Athletic reports.
He's taking over the rotation spot vacated by Cristian Javier (neck), who was placed on the 15-day injured list over the weekend. The Astros have a couple off days over the next week, and Javier could be back shortly after that, so Arrighetti may just be in line for a spot start. The rookie was bludgeoned for seven runs over three innings in his major-league debut earlier this month in Kansas City but was better in his second start April 15, holding Atlanta to two runs over four frames.