Manu Tuilagi's groin injury will be assessed by Leicester on Monday with the club expecting the centre to miss England's autumn Test opener against world champions New Zealand next month.
Tuilagi hobbled off just 15 minutes into Leicester's 25-18 Champions Cup victory over Ulster on Saturday after suffering a recurrence of the groin problem which saw him miss three matches earlier this season.
Sunday was a rest day for all the Tigers players but Tuilagi will undergo tests with the club's medical staff on Monday.
The club anticipate the 23-year-old will be sidelined for at least three weeks, which would rule him out of England's crunch game against the All Blacks at Twickenham on November 8.
England head coach Stuart Lancaster will be hoping Tuilagi can recover in time for subsequent matches against South Africa on November 15, Samoa on November 22 and Australia on November 29.
England are already missing a number of key players with the likes of Alex Corbisiero, Mako Vunipola, Tom Youngs and Geoff Parling all out of the autumn fixtures.