Saints assistant coach Alan Dickens admits he was surprised to see George North remain on the field for Wales on Friday night.
North suffered two heavy blows to the head in the 21-16 Six Nations defeat to England at the Millennium Stadium.
He underwent an off-field assessment for eight minutes during the first half after taking a boot to the face and fell to the floor after a sizeable impact in the second period.
However, he was not withdrawn by Wales, with the Welsh Rugby Union (WRU) issuing a statement that said the second incident had not been seen, and that the 22-year-old was symptom-free on both occasions.
Governing body World Rugby have now launched an investigation into whether “all concussion” protocols were followed by Wales.
But Dickens is not sure whether Saints have engaged in discussions with the WRU over the North situation.
“I was surprised that he stayed on, but other than that I can’t really say more than that about it,” said Dickens.
“They said they didn’t really see it and he’s got up and got on with it, but in terms of any conversations with us and Wales, I don’t know if it’s happened.”
North must now undertake a graduated return to play protocol and is set to miss the trip to Murrayfield to face Scotland next Sunday.