England are waiting on the result of an x-ray to Maro Itoje, who is a doubt for the autumn internationals after injuring his hand in Saracens' Champions Cup win over Scarlets on Saturday.
The 21-year-old suffered the injury after being caught in a tackle shortly after half time. He played no further part in the game and was due to undergo the x-ray to determine any possible fracture. Saracens said he would also need to see a specialist.
"Maro came off with a sore hand," said the Saracens director of rugby, Mark McCall. "He will be examined and have an x-ray after which we will know more."
Saracens are due to give an update on Monday.
Should Itoje be ruled out of the series, which opens against South Africa at Twickenham on November 12, it will be another blow to coach Eddie Jones who has already seen four flankers, second row George Kruis and several backs, including Manu Tuilagi ruled out.
Itoje had been touted to move from lock, where England are well served with replacements, to the problem area of flanker following the injuries to James Haskell, Jack Clifford, Mike Williams and Sam Jones.
In the autumn series, England also play Fiji on November 19, Argentina on November 29 and Australia on December 3.