Sporting Lisbon have confirmed that William Carvalho has fractured his tibia.
The injury, which is believed to have been suffered at the recent European Under-21 Championships, is likely to sideline the 23-year-old for the next three months.
As a result, a proposed switch to the Premier League with Arsenal has been thrown into doubt, with the Portuguese midfielder expected to undergo his rehabilitation at Sporting.
In the past, Carvalho has been linked with Arsenal's domestic rivals Manchester United, as well as clubs in Spain and Italy.
