Ben Te'o is a major doubt for England's November internationals after suffering an ankle injury that is set to rule him out for a month.
Te'o was injured early in Worcester Warriors' victory over Brive on Saturday and may be out for a longer period of time if the powerful centre requires surgery.
With England due to play Argentina, Australia and Samoa next month, Te'o appears unlikely to recover in time to feature for Eddie Jones' side.
Worcester coach Carl Hogg told the Worcester News: "He's being assessed currently and will head back down to Cardiff on Monday to see whether he'll go down a surgical route or whether it'll be managed conservatively.
"He's expected to be out for at least a month but we'll find out more next week once the swelling has settled down and it'll give us a better idea of timeframes."
Te'o has eight caps for England and was a member of the British and Irish Lions squad for the drawn 1-1 series against New Zealand.