Saints boss Jim Mallinder has revealed Tom Wood twisted his ankle in Saturday’s 32-8 defeat to Racing Metro.
The flanker was forced off in the second half of the Champions Cup loss at Franklin’s Gardens.
It will be a worry for England, who face Wales in a Six Nations opener at the Millennium Stadium on February 6.
But Mallinder is hopeful his influential forward has not suffered any serious damage.
“Tom Wood twisted his ankle, hopefully it’s nothing more serious than that, but he was certainly sore and we thought it was sensible to get him off,” said the director of rugby.
Salesi Ma’afu added to Saints’ woe as he was also taken off after half-time.
But Mallinder is optimistic the Australian prop will be fit to face Leicester in the LV= Cup on Saturday.
“Salesi’s fine,” he said. “He banged into the head of Samu Manoa, which is something you shouldn’t really do.”