A source close to Wales full-back Leigh Halfpenny, who is set to join Wilkinson's Toulon next season, has apparently confirmed the story.
Iconic fly-half Wilkinson - who will be best remembered for his dramatic late drop goal that clinched England's World Cup success against Australia in the 2003 final - claimed the European Player of the Year award last year, but at 34 said he had been taking it "game by game".
He is England's all-time leading points scorer with 1179 points from 91 games.
"Jonny is finishing," said a source in the Rugby Paper. "He'll be calling it a day once the season is over and after that he'll be helping Halfpenny settle in.
"Leigh's always willing to learn and having Jonny as his mentor will make him even better."
Wilkinson hinted in February that he was considering his future as a player with The Times confirming the story this month. Wilkinson announced his retirement from the international scene in December 2011. Despite his haul of caps, his career was disrupted by a series of injuries.
He was Six Nations winners with England in 2000, 2001, 2003 and 2011, and a Heineken Cup winner with Toulon last year.
"Some weeks I walk off the field and think: 'God, I'm useless'," Wilkinson said in The Guardian last month.
"One thing I don't want to do is put myself in a position where the desire and the enjoyment is no longer there. That is hugely unfair to whoever I'm playing with. It's a day-by-day thing.
"My role is developing. I now spend most of the week in training, helping my team-mates approach the game differently. I've accepted that for a long time, but that doesn't change the fact that, deep down, I cannot stop competing."
- Sports & Recreation
- Leigh Halfpenny