Lawes joins England's 'sickbay squad'
Lawes was pulled out of North Hampton Saints' Premiership encounter with Gloucester at the 11th hour on Friday, as a result of a knee complaint.
It has since emerged the injury is serious enough to put him in the 'doubtful' category for England's year-end Tests – which start against South Africa on November 12.
England coach Eddie Jones will already have to do without the services of a number of key players – including star locks George Kruis and Maro Itoje.
James Haskell, Jack Clifford, Sam Jones and Mike Williams are the other players ruled out through injury.
Northampton Director of Rugby Jim Mallinder hinted at a two-week lay-off for Lawes, but it could be longer.
"He [Lawes] has a bad knee," Mallinder said, adding: "He did it a couple of weeks ago and missed the [European Cup] game against Montpellier with it.
"We thought it had improved and he played last week [in the European Cup defeat against Castres] with no problem, but then midweek he trained again and it reacted.
"He will have a scan on it to determine the extent of the injury.
"Fingers crossed there is not too much damage and he will be ready in a couple of weeks."
After facing South Africa, England play Fiji on November 19, Argentina on November 26 and Australia on December 3 – all matches at Twickenham.
