Manu Tuilagi has suffered a recurrence of the groin injury which forced him to miss three Aviva Premiership matches for Leicester Tigers earlier this season.
The England centre was forced off early in Leicester's 25-18 win over Ulster in the European Rugby Champions Cup on Saturday and could now be forced to sit out the upcoming autumn internationals.
Tigers director of rugby Richard Cockerill told BBC Sport: "It's a recurrence of his groin, which is not great. That was three weeks last time. That's going to be an issue for him, with us, and obviously with the autumn series.
"He just went to accelerate and he felt his groin go. The way he plays, you just can't play with that sort of problem."
England are due to face New Zealand on November 8, with fixtures against South Africa, Samoa and Australia also scheduled for next month.
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