The sanctioning body handed down significant penalties against Michael Waltrip Racing, resulting in MRW's Truex losing his berth in the post-season Chase.
NASCAR said the Waltrip team manipulated the outcome of Saturday's regular season-ending race at Richmond International Raceway when Clint Bowyer, the driver of the No. 15 car for MWR, deliberately spun out with seven laps left in order to force a caution and help Truex.
Newman was leading at the time but ending up finishing third and missed a shot at the final Chase wild card berth, which he lost to Truex on a tie-breaker.
After reviewing the race, NASCAR Vice President of Competition Robin Pemberton announced Truex was out and Newman was in.
"As the sport's sanctioning body, it is our responsibility to ensure there is a fair and level playing field for all of our competitors, and this action today reflects our commitment to that," he said.