That injury has seen him miss the last seven matches with last weekend's European defeat to Brive coming too soon for the 22-year-old, who was included in Joe Schmidt's Six Nations squad.
However Lam has revealed that Henshaw could be in contention for Saturday's clash against Russian side Enisei-STM, which Connacht have to win to stay in contention for the Challenge Cup quarter-finals, provided he gets the all-clear beforehand.
"He went for that scan (last week) and it showed that he wasn't quite ready, he needed another week or two. That's why he didn't go to Brive," said Lam.
"Again he feels pretty good with it, but he needs the final sign-off from the scan on Friday.
"He's trained this week and will train for the rest of the week and prepare to play."
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