On January 9, 2019, GMS announced the team had parted ways with Sauter. He later rejoined ThorSport to drive the No. 13. Sauter won his first race of the season at Dover in May. At Iowa, Sauter was parked by NASCAR for wrecking Austin Hill under caution on lap 139 of 200. As a result of the incident, he was suspended for the following week's race at Gateway, although he was given a waiver, allowing him to remain playoff eligible if he won a race. Myatt Snider was announced to substitute for Sauter at Gateway. Sauter was eliminated from the playoffs at Las Vegas when he finished 29th after experiencing an engine failure that also plagued three other trucks. Ilmor, the manufacturer of the engines, took responsibility for the NT1 engines that suffered from severe detonation due to the combination of the high engine load condition combined with the extreme weather conditions in Las Vegas. Despite Ilmor's announcement, NASCAR denied ThorSport's request to reinstate Sauter and Grant Enfinger into the playoffs. At Talladega, Sauter appeared to have won the race, but was penalized and placed in 14th for blocking Riley Herbst below the yellow line on the final lap, effectively giving the win to Spencer Boyd.