Clarke will undergo tests next month and Lam is hopeful that everything will become clearer after that.
"Craig has more scans planned for the beginning of April to check where he's at. It will certainly give us more clarity," said Lam.
"It (his concussion) is still on-going. He's been out for a while, but for all players, rugby as a game, it could be gone just like that. You never know, it's just the nature of the game we play.
"The boys don't see him all glum and hanging down. They see the qualities of the man, helping others; mentoring others; passing on his information; encouraging guys; still forming part of the analysis of other teams."
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