Owen had been in line for a possible recall for England for next month's friendly in Spain but that scenario evaporated when he limped off early in his side's 2-1 defeat at Manchester City.
Magpies boss Joe Kinnear said: "Owen is on crutches. He has cracked his ankle. He'll have a scan on it, but doctors are saying he could be out for six weeks."
Kinnear added: "Joey will be out for ten weeks. He has cracked the bone in his right foot. It's a metatarsal.
"It's tough for us, seriously tough."