The Wales prop had been playing through the pain barrier in the RaboDirect PRO12 with Ospreys but his injury may yet be an international blessing as Jarvis looks to make his debut for the Principality.
Scarlets rookie Samson Lee has been called up as cover while Blues' Scott Andrews is another alternative - but Humphreys hopes Jarvis might be promoted to take his bow.
"Adam has been struggling with his knee for four or five weeks now," said forwards coach Humphreys.
"He's put the team first, he's played through a bit of pain but on the weekend he re-injured that area.
"We'll just have to wait on medical opinion: he could be right in the next week or so or he could take a little bit longer than that.
"It's an area in the past that [Wales] haven't had a lot of strength in but hopefully Aaron will get some game time, some opportunities and push his claim forward."
However while Adam Jones is a doubt Ospreys back-rower Ryan Jones should be fit for international duty - where he is being tipped as a replacement for injured Dan Lydiate.
Jones has got a dead leg and is a doubt for this week's RaboDirect PRO12 game against Connacht but is expected to be fit for the Argentina game.
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