NORTH Melbourne's first-round draft pick Ben Cunnington says just a week of training with foot soreness could have grounded him for two months.

Scans mid-week showed Cunnington had a hot spot on a bone in his right foot, which is often the first sign of a forming stress fracture.

The 18-year-old, who will be sidelined for as many as four weeks, felt some discomfort after North returned to pre-season training on Monday.

"It wasn't even a tough session, it was just pretty light," he said. "I went home and started to feel a bit of pain in my foot.

"Throughout the pre-season I'd been sore in my knees before, but when you wake up after a sleep you're alright. I woke up and I could still sort of feel it."

Cunnington said that North had made a strong point of telling its draftees to contact medical staff if they ever suffered soreness, which encouraged him to speak up.

Last year, a stress fracture in the right foot of midfielder Liam Anthony went undetected until the first week of the season.

He had been picked to play but was forced out of the side and didn't make his AFL debut until round 13.

"I didn't think I'd have that (a stress fracture), because it wasn't that painful," Cunnington said. "I could have trained.

"I let them know straight away and we got on to the scans as soon as possible and it ended up showing I did have a hot spot.

"They said if I had have trained on it for a week, like I felt I could, it would have been double - so eight weeks out. They were pretty happy I picked it up early."

Cunnington was put on crutches on Thursday and arrived at training at Arden Street on Friday wearing a moon boot on his right leg.

He said that club doctor Con Mitropoulos was hopeful he could be running within three weeks. He has to wear the boot for two.

"I've got to rest my foot but I've still got to do all the hard yards in the gym just to keep me fit so I don't fall behind the other fellas," he said.

Cunnington added that North's coaches had indicated the injury could rule him out of NAB Cup contention, although he still had his sights on round one.

"All the young ones are really keen to play round one," he said. "I talked to a few coaches and the main thing is to get my health right first and let all my training speak for itself."

Anthony completed his first full training session since mid-November, having recovered from a deep laceration to his left ring finger.

Though the finger was still heavily bandaged, he had little trouble marking and disposing of the ball.