Southampton manager Nigel Adkins has revealed that the club will assess Adam Lallana's knee injury in the next two days.
The captain was forced off in the first half of Saturday's 1-0 win over Reading in the Premier League.
"We've got him in a brace and he is on crutches at the moment. That is standard procedure," said Adkins.
"He has got a knee injury and what we will do is assess that over the next 24 to 48 hours and that will give us a better prognosis to how long potentially he will be out for.
"It could be short, it could be longer. We don't know so we won't guess at the moment."
Saturday's victory saw the Saints move out of the relegation zone and up to 15th place in the table.