NFL Week 3 Upsets Expose Sportsbook Mispricing of Backup Quarterbacks

Week 3 of the 2026 NFL season delivered a stark reminder that sportsbooks continue to misprice quarterback changes, as backup signal-callers compiled a 7-3 straight-up record and sparked multiple upsets that hammered major favorites.

The week's most striking result came Monday night when 38-year-old Case Keenum, making his first start since 2023, led the Chicago Bears to a 27-7 victory over the heavily favored Philadelphia Eagles. Chicago entered as 3.5-point underdogs despite being without both starting quarterbacks Caleb Williams and Tyson Bagent due to injuries. Keenum completed 24 of 34 passes for 247 yards and two touchdowns, a performance that prompted Craig Mucklow, vice president of trading at Caesars Sportsbook, to note that "the bigger mistake has been in the original numbers, not the betting that followed."

The Eagles were not alone in falling to backup-led teams. On Sunday, the Washington Commanders, led by Marcus Mariota, upset the defending champion Seattle Seahawks 33-31. The pattern extended across multiple backup situations. Seattle's Drew Lock went 2-0 while Sam Darnold recovered from injury, and the Minnesota Vikings' Carson Wentz led the team to a 2-0 record. The New York Giants won with Jameis Winston, though they sit 1-1 overall, while the Atlanta Falcons with Cooper Rush remain 0-2.

Beyond the backup quarterback trend, Week 3 saw five significant favorites lose outright, including the Green Bay Packers (at -4.5), Cincinnati Bengals (-2.5), Carolina Panthers (-1.5), and Seattle Seahawks (-8.5). The Falcons, despite being 4.5-point underdogs, demolished Green Bay 35-14. The Pittsburgh Steelers upset Cincinnati, while the Cleveland Browns defeated Carolina. The San Francisco 49ers and Detroit Lions, though winners, failed to cover their respective 7.5-point spreads.

Joey Feazel, head of football at Caesars Sportsbook, noted that "later afternoon games turned into an Over bettor's dream, with points piling up and Totals cashing across the board." The Vikings' 23-16 win over Tampa Bay and the 49ers' 36-30 victory over Arizona exemplified this trend. Notably, the Ravens' 34-31 win over the Cowboys in Rio generated lighter than anticipated handle, surprising given the typically popular weekend window.

Player proposition betting proved especially rewarding for bettors. Nine of the ten most-backed players at Caesars reached the end zone, turning touchdown parlays into reliable sources of winning tickets. This consistency in touchdown outcomes created what Feazel described as "a dream Sunday for player prop bettors."

From an industry perspective, the week underscores a persistent challenge for sportsbooks: accurately pricing outcomes when roster changes occur mid-season. The 7-3 backup quarterback record represents substantial value leakage, particularly when teams enter games with significant injury circumstances. As the 2026 season progresses, operators may need to reassess their approach to rapid quarterback substitutions and the corresponding line adjustments, ensuring that initial oddsmaking reflects the true competitive dynamics rather than narrative expectations around starting versus backup signal-callers.