Mathew Tait is concerned about becoming old before his time. He is recovering from sciatica that has affected his back and right hamstring, which was treated with an epidural injection six weeks ago. To his amazement, he has found himself cultivating a vegetable patch in his back garden, having turned to gardening to fill the hours since his degree in biomedical sciences was put on hold after his move from Newcastle Falcons to Sale Sharks in the summer.

“I feel as though I’m 22 going on 50 at the moment,” he said. “Sciatica and a veg patch, all I need now is an allotment and a whippet and I’ll be a proper old man.”

It would hardly be surprising if Tait felt older than his years, for he has experienced more than the average 22-year-old rugby player. It will be four years in February since, only months after his A levels, he was given his international debut against Wales by Andy Robinson, the England head coach, then promptly dumped for the next game.

He was then put through an ill-advised weight-gain programme by the RFU that succeeded only in taking the edge off his startling pace. Trimmed down again, he gradually rebuilt his confidence to become one of England’s leading lights in the World Cup in France last year.

But the stop-start nature of his career has continued this season as injury and confusion over his best position have hindered his progress at Sale. Against Bath this afternoon, he will start on the bench as he continues to work towards full match fitness.

“I’ve really enjoyed the move, it’s the first time away from my parents, I’ve moved in with the girlfriend and we’ve made lots of friends,” he said. “It’s just the rugby that’s frustrating.”

This was the year that Tait decided, with the support of the England coaches, to make permanent his switch from outside centre to full back, where many of the game’s leading thinkers believed that his elusive broken-field running could best be exploited.

He was one of two designated full backs, along with Josh Lewsey, named in the first elite player squad of Martin Johnson, the England team manager, in July, only to be ruled out of the autumn internationals by his sciatica. In his absence, Delon Armitage established himself at full back and is sure to be chosen when Johnson revises his elite squad on January 14.

Tait’s attempts to grow into the No 15 shirt have been further hampered by Sale’s use of Charlie Hodgson, the fly half, as defensive sweeper and Philippe Saint-Andre, the Sale director of rugby, said last week that he believes outside centre to be Tait’s best position.

So what is Tait’s preference now? “Oh, I don’t know,” he said, with a rueful smile. “I’ve spoken to Brian Smith [the England attack coach] and a decision will be made soon. I’ve done a lot of work on my full-back play and that won’t be lost if I move back to centre. It’s another string to your bow. But ideally, I’d like to focus on one position.”

The signs are that the full-back experiment is likely to be put on hold and possibly abandoned altogether. “Mathew has the potential to be a world-class outside centre,” Kingsley Jones, the Sale head coach, said. “He could also become a top-class full back, but he needs some clarity and continuity at the moment. England are happy for him to play at 13, he just needs to get some fitness and confidence back, then he could be challenging for two positions for England.”

When he gets in from the garden and kicks off the wellies, Tait is a voracious reader and his latest tome has been Marshall Goldsmith’s business bestseller, What Got You Here Won’t Get You There, a treatise on the need to embrace change and flexibility.

But perhaps Tait has been too flexible for his own good recently and now he needs a period of stability. There is plenty of time yet for one of the game’s brightest talents to find his calling and come of age.