Head coach Marinus Dijkhuizen has suggested that Brentford playmaker Jota faces up to four months on the sidelines.
The 24-year-old, one of the Bees’ outstanding players last season, was ruled out of Saturday’s 4-2 win at Bristol City.
He picked up the injury in last weekend’s draw with Ipswich.
Earlier this week his team-mate Andreas Bjelland was ruled out for the season with a knee ligament injury.
“It was an awful week,” said Dijkhuizen. “First the cup defeat to Oxford and the big injury to Andreas Bjelland.
“Jota is now out for three or four months. That’s a lot of quality players injured in one week.”