The Newcastle Falcons star looks set for a further two months on the sidelines after discovering he lacerated his left kidney in his latest comeback in the Guinness Premiership against Bristol on Friday.
It is Wilkinson's 10th injury since landing the drop-goal to win the World Cup nearly three years ago - since when he has not played international rugby.
"I can't really pinpoint the hit which did the damage," he said.
"I felt it but was able to carry on. I don't think it really hindered the way I was playing.
"The annoying fact is that it seems that playing on may have made it a lot worse.
"What clearly has happened is I must have taken a hit through the front of my stomach which smashed my kidney into a rib, which then lacerated the kidney.
"I was in discomfort throughout the weekend. It was after that I had the scan, which showed quite a bad laceration.
"It's so uncomfortable, training would have been out of the question. I still can't walk without feeling it.
"Kidneys do heal quite quickly, but the specialist has seen the scans and says that I cannot do anything at all for at least a month. I'm so disappointed."