Both starting quarterback Jameis Winston and top receiver Michael Thomas are set to miss the New Orleans Saints' Week 4 game against the Minnesota Vikings in London.
The Saints quarterback's health has been deteriorating for weeks.
The top choice in the 2015 NFL Draft received a hit to his back in the fourth quarter of the team's victory over the Atlanta Falcons in Week 1, which worried the medical staff.
NFL insider Jay Glazer reported Winston suffered four back fractures and has been experiencing significant discomfort a week after the impact.
Winston has been absent from the team's first few days of practise in preparation for their Sunday morning game in England.
While head coach Dennis Allen and the quarterback attempted to assuage fans' fears by claiming that the missed practises were all part of a plan to ensure Winston was ready for game day.
Jameis Winston, who did not practise today for the third day in a row, is unlikely to play on Sunday.
In Jamie's absence, Andy Dalton will take the field against the Vikings.
Jameis Winston is the seven-year veteran and three-time Pro Bowler.