Garner has scored 14 goals so far this season (Getty Images)

A scan has revealed the 19-year-old damaged anterior cruciate ligaments during the 1-0 win at Crewe on Tuesday.

Carlisle manager John Ward told BBC Radio Cumbria: "Worst-case scenario, Joe could be ruled out for up to nine months.

"We think we are looking at a long time out for Joe and that's a massive blow."

He added: "It's as bad as it could be really."

Garner has been referred to a specialist in Bingley who will assess the full extent of the injury and determine whether the teenager will need surgery.

Meanwhile, 19-year-old defender Dan Kirkup has joined Blue Square North side Workington Reds on a month's loan.

Ward told the club website: "We told Dan that he was going to be made available in the summer, so he was aware of that from the outset.

"We were determined to try to help him get something set up, and we think this move will be good for him and for Workington.

"This gives Workington the chance to have a look at him, and then we can take it from there."