Leicester and England are sweating over the fitness of Manu Tuilagi after the centre suffered a knee injury against Saracens on Sunday.
Tuilagi, who was recently absent with a groin problem, was helped from the Welford Road action after just eight minutes in the 16-12 loss.
England coach Eddie Jones was in the crowd for the Premiership game, with Tigers boss Richard Cockerill giving an update after the match.
"He got a bang on the outside of his right knee and we don't know the extent of the injury yet," said Cockerill.
"His groin is feeling great so that's one good thing, there's always a positive.
"It's disappointing because he is important to us.
"Normally it's 24 hours so we will see how it has settled down in the morning and see if there's any swelling.
"It might just be a bang and a bit of swelling, it might be a couple of weeks. I'm just guessing."