The midfielder was stretchered off late in the League Two side's 1-0 win at Gillingham on Boxing Day, and scans have confirmed that he has sustained an anterior cruciate ligament injury.

Longstaff's loan spell with the U's was due to expire in January and he will now undergo his rehabilitation at the Magpies' Benton training ground.

The 22-year-old made ten appearances during his time at the JobServe Community Stadium, and everybody at Newcastle United wishes him a speedy recovery as the Magpies' medical staff support him on the road back to full fitness.