England pair Dylan Hartley and Courtney Lawes face a nervous wait to discover if they will be fit for the November Tests after suffering knee injuries in Northampton's 16-6 defeat against Saracens on Saturday.
Hartley and Lawes were both forced off before the start of the second half and Northampton director of rugby Jim Mallinder admitted they will be assessed by England when they meet up with their international colleagues on Sunday.
"They've done something, but we will know a lot more later," Mallinder said.
"I think Lawes and Hartley are the sort of characters that if they had just got a knock and they will be running around on Monday they wouldn't have come off.
"Courtney tried to carry on, but he was unable to do so. You want them on the field and getting through games. It was disappointing they had to go off."
Lawes had a long lay-off last season with an injury to his right knee, but went off in the 27th minute with a problem to his left knee.
Hartley took a blow just before half-time and did not emerge for the second half, though Mallinder could not say which knee the England hooker had injured.
With Tests against Fiji on November 10, Australia on November 17, South Africa on November 24 and New Zealand on December 1, England coach Stuart Lancaster will be fretting over the duo's fitness.
He will be hoping they recover for Northampton's clash against Leicester at Welford Road so they can prove their fitness for the internationals.
"Courtney and Dylan join up with England tomorrow and we will have to wait for a decision whether they are rested or not for Leicester," Mallinder added.
"Stuart will look to retain his starting 23 and I guess the others will be returned to their clubs."