No team has completed an undefeated 17-game NFL regular season in over five decades, and current trader consensus reflects the extreme difficulty posed by the expanded schedule, widespread roster injuries, and league-wide parity. Recent offseason roster turnover, combined with challenging early matchups for projected contenders, further reduces the odds of any club avoiding a single loss through Week 18. Historical patterns show that even dominant teams encounter setbacks from rest disadvantages, travel, or in-season injuries that sideline key contributors. While a strong start remains possible for top clubs, the cumulative physical and competitive demands across 17 contests make a perfect record exceptionally rare.