Courtney Lawes is a doubt for Eddie Jones ahead of England's Autumn internationals after withdrawing late on from the Northampton side that beat Gloucester 23-20 at Franklin's Gardens on Friday night.
Northampton director of rugby Jim Mallinder revealed that the second row will go for a scan on a knee injury this week.
With Maro Itoje and George Kruis already out of the upcoming fixtures, England boss Eddie Jones was looking to Lawes to step into the second row, but will have an anxious wait ahead of the opening clash against South Africa on November 12.
"Courtney has a bad knee, he did it a couple of weeks ago and missed the Montpellier game with it," said Mallinder. "We thought it had improved and he played last week with no problem, but midweek in training it reacted so we will have to have a scan on it to see the extent of the injury.
"I am not sure if he will be ready for the Autumn Internationals, fingers crossed there is not too much damage and he will be ready in a couple of weeks' time."
Eddie Jones summoned Sale Sharks second row and no. 8 Josh Beaumont to their training camp in Portugal on Saturday night as injury cover for Lawes.