Sam Jones' hopes of making his England debut have been hindered by an ankle injury sustained in training.
The Wasps flanker is a contender to deputise for the injured James Haskell when England face South Africa, Fiji, Argentina and Australia across November and December.
However, the uncapped forward has returned to his club for further analysis on his injury.
"Wasps back-row forward Sam Jones sustained an ankle injury during an England training session this morning [Tuesday] at Brighton College," read a statement from the Rugby Football Union.
"Jones will undergo further examinations to diagnose the full extent of the injury."
England are aiming to build on a superb start to head coach Eddie Jones' tenure.
Under Jones, England secured a first Six Nations Grand Slam since 2003 and whitewashed Australia 3-0 in June's series down under.