Rio's Peterborough United return delayed after a '1 in 10,000' reaction to an injection

​That’s why the 24 year-old left-back, a £500k summer signing from Crewe Alexandra, has not been involved in either of the last two Posh Under 21 matches.

But there is still relief in the Posh camp as a visit to a specialist has allayed fears Adebisi’s return to action has only been delayed by a couple of weeks.

Adebisi, who was an ever-present for Crewe last season, has yet to play a competitive game for Posh because of a knee injury that required surgery in August.

"We were worried,” Posh boss Darren Ferguson admitted. “We delayed Rio’s return two Tuesdays ago because of some swelling which we didn’t think was too serious, but it didn’t improve so we sent him to a specialist.

“We then found out Rio had suffered a 1 in 10,000 chance of a bad reaction to an injection, which was typical of our luck this season, but having got to the bottom of the problem it was easily resolved.

"He’s on different medication now and he’s fine. We’ve had to push his return date back a little and he won’t now be ready for the Northampton game.

"We will try and get a friendly game arranged for him in the middle of December and then take it from there, but we are just relieved we discovered the problem.”