Tippett suffered the injury after copping a knee to the back during a VFL practice match on the weekend while playing for Werribee against Footscray.
“Joel reported immediate pain and spasms in his lower back,” North Melbourne director of football Geoff Walsh said.
“Things have now settled and he will have follow up scans as part of his treatment.
“The word ‘fracture’ is never a good one when it comes to injuries, but in Joel’s case, it is not one that will interfere significantly with his conditioning or long term spinal function.
“There’s no need for surgery and our medical team is certainly aiming at getting him back in about four weeks.”