Peterborough United goalkeeper could be out for six weeks, but Butler back next week

The results from a scan undertaken on Monday were not what Posh wanted to see. Cartwright will return to parent club Hull City for the start of his recovery period.

The 20 year-old has started just one Posh game, the 2-1 EFL Trophy defeat at home to Stevenage last week after which he felt a niggle in the thigh area.

"It’s a big blow for us and for Harvey,” Posh boss Grant McCann said. “He will be out for 5-6 weeks and he will be treated initially by the Hull medical staff.

"He hasn’t been able to get going with us so far which is a real shame. Harvey is a top young goalkeeper, but he’s not in a great place right now.

"I had him at Hull and he never missed a day’s training. He’d often train twice a day with the senior team and the under 21s so to see him pick up an injury with us is very disappointing, but we have to look at the big picture and get him fit again.”

Cartwright is on loan at Posh until the end of the season as is Chelsea 'keeper Lucas Bergstrom who has started the season in great form.

"Lucas has stepped up very impressively,” McCann added. “He’s already and excellent goalkeeper, but he’s going to become a top, top, number one.

"He’s been unbelievably good so far and you can see his confidence growing. Let’s hope he continues to make big saves that help us win matches.”

Posh full-back Dan Butler, who has been absent with a serious ankle injury since December, could have some minutes in next week’s under 21 fixture at Sheffield United.