Coventry City have received a double injury blow, with teenage forward James Maddison and defender Jordan Willis set to miss sizeable periods of the season.
Maddison, 18, was forced off in the sixth minute of Saturday's 2-1 defeat by Walsall with an ankle injury.
A scan has revealed Maddison could be out until January with the problem.
Willis, 21, was also hurt in the match and has been told his knee injury will need surgery that is likely to keep him on the sidelines for up to eight weeks.
The news is a setback for Tony Mowbray's in-form side, who won their first three League One games before losing to Walsall.
Maddison scored two goals in 18 games in his debut season last term and has been a key figure in the side's excellent start to the campaign.