Chris Boyd issued a positive injury update on Dan Biggar after Saints' 67-17 win against Sale Sharks on Saturday afternoon.
Biggar was forced off after just 20 minutes of the Gallagher Premiership game at Franklin's Gardens.
The Wales star, who had featured in his country's first two Six Nations matches and will be needed for the huge game against England in Cardiff next Saturday, was replaced by Tom Collins.
That meant George Furbank went to fly-half, with Ahsee Tuala switching to full-back and Collins taking the Samoan's place on the wing.
And Saints went on to register a resounding victory.
After the game, Boyd was asked about Biggar's withdrawal.
And the Saints boss said: "He came back from Italy with a really low-grade MCL strain in the knee and was keen to play.
"He trained really well on Thursday and felt really comfortable but he just caught it again and that was precautionary.
"Despite the fact (England boss) Eddie Jones was probably keen for me to keep him on the field, we decided in the best interests of his health and safety to remove him.
"He probably could have played on but I thought George (Furbank) did a good job in his space when he came off.
"I'm no medical man but I would be surprised if Dan isn't fine to train with Wales this week."