Earls has been struggling with a patellar tendon injury that he picked up over the off-season, and after consultation with a specialist it was decided that he will need an operation.
He had been hoping to manage the injury through conservative rehabilitation but it has now been decided that surgery will be required after failing to appear in the GUINNESS PRO12 yet this season.
It's not the first time Earls has struggled with knee problems, having already missed last year's November Tests with patellar tendonitis, and Foley is wishing his star a speedy recovery.
"Keith was, a couple of weeks ago, penciled in for a return in this game [against Leinster on Saturday]," said Foley.
"That's what we were looking at about three or four weeks ago. Unfortunately, on his return, he was sidestepping and felt something in his knee.
"We had to go and get that further investigated. We did and it's obviously meant surgery today. Our thoughts are with Keith.
"I think he's played nine games for Munster over the last season, so we just want him fit, healthy and back playing for Munster."
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