In 2017, Starr left RSS to drive the No. 99 full-time for B. J. McLeod Motorsports, fielded jointly with SS-Green Light. Starr ended up getting his first career Xfinity Series top-5 in the July race at Daytona, a race he was not even supposed to run. SS-Green Light had planned on replacing Starr with Korbin Forrister for this one race, but when he became ill, Starr got back in the ride, and went on to finish the season in the No. 99. In November, Starr made his return to the Cup Series at the 2017 AAA Texas 500, in which he drove the No. 66 Chevrolet for MBM Motorsports.