The retired Scotland striker won't play again for Vancouver Whitecaps this term, with the Canadian side already out of the running for the Playoffs.
Former Old Firm hitman Miller, 33, has been struggling with various hamstring and groin knocks all season and has missed more than a third of the season in North America.
He's now suffering from tendinitis in his knee and has flown to Scandinavia for treatment.
Vancouver boss Martin Rennie said: "Kenny's had tendinitis in his knee for most of the season and it's just got worse and worse.
"So he's going to see a specialist on that and once we have an update on that we'll let everyone know."
Miller signed a new deal with Whitecaps that will see him through to summer next year, but he will be free to speak to other clubs from January, with Rangers repeatedly linked with him.
He hit eight goals in 19 starts this season and bowed out of Scotland duty after netting at Wembley against England in August.
His former Ibrox team-mate, Hull goalkeeper Allan McGregor has been ruled out for up to six weeks with a thigh injury, Tigers boss Steve Bruce has announced.
McGregor has played a key role in Hull's impressive return to the top flight but is now set for a spell on the sidelines after sustaining the problem at Everton on Saturday.
"We've just found out that Allan is going to be out for five or six weeks," Bruce said.
"As I've said repeatedly, injuries are the one area where we needed to stay fit and healthy and this one couldn't have come at a worse time.
"Allan will be a big miss for us because he has played very, very well and we wish him a speedy recovery."
Steve Harper, brought in over the summer after his contract at Newcastle expired, will deputise, starting in this weekend's trip to Tottenham.