Northampton Saints face an anxious wait to discover the full extent of second-row Courtney Lawes' knee injury.
Lawes was forced from the field just ten minutes into his side's defeat to Leicester Tigers in the Midland's derby at Welford Road which the home side won 27-16 at the weekend.
With crucial Heineken Cup games against Edinburgh and Castres over the next fortnight Jim Mallinder will be hoping he can call upon the services of the England power house.
Mallinder will also be waiting on further medical examinations on Shane Geraghty who left the field with a suspected fractured eye socket.
"They are tough lads I am hoping that the injuries are not too serious," said the Saints director of rugby.
"To lose two of our England men was not the best, but I am not blaming that for the result. Leicester played better than us."
Northampton return to Heineken Cup action on Friday evening when Edinburgh are the visitors to Franklin's Gardens before they travel to France for their final Pool 1 encounter against Castres Olympique on Saturday January 22.