New York Giants wide receiver Victor Cruz missed team practice on Wednesday.
Cruz injured his neck during the team's win over the Philadelphia Eagles last month, but returned to the field having been treated.
With the Giants on their bye week last weekend, Cruz was afforded a timely rest and practised as normal at the start of this week.
However, his missed practice causes some concern for head coach Tom Coughlin, who will need his star man for this Sunday's match with the Oakland Raiders.
Couglin told the New York Post: "I wouldn't call it a setback, but when a guy isn't practising, obviously it's an issue. They're just gonna hold him to make sure he doesn't have any further incidents.
"He feels better, quite frankly. I think he probably could practice if we really needed him to practise but we're being cautious and everyone in here hopes that he will be prepared to go tomorrow."
Cruz leads the team in terms of receptions and yards this season, with 677 yards from 47 catches so far. He also has four touchdowns to his name.