"He's a little uncomfortable at the moment," he said post-match.
"He has a bit of strapping on his knee. I'm not sure exactly [how he is] to tell you the truth.
"He will get a scan tomorrow [Sunday] and will see the extent of it."
Injury puts Johnny Sexton in doubt for Six Nations
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Injury puts Johnny Sexton in doubt for Six Nations
Johnny Sexton could face a race against time to be fit for the Six Nations after suffering a knee injury in Leinster's win over Northampton Saints.
The Leinster and Ireland playmaker suffered suspected ligament damage to his right knee in Saturday's Champions Cup game between the leaders of the Premiership and Pro14.
“Johnny has taken a bang to the knee and we’ll see how much damage has been done,” Leinster boss Leo Cullen said.
The Six Nations kicks off in just over seven weeks with Ireland at home to Scotland.
