Wilkinson has suffered a catalogue of serious injuries since 2003
Newcastle are "optimistic" Jonny Wilkinson will make a full recovery after revealing that he underwent successful knee surgery on Friday.
The 29-year-old England fly-half was operated on after he dislocated his knee in their 39-23 loss to Gloucester.
"Reports are that it went well," said Newcastle rugby director Steve Bates. "The [medical team] are optimistic."
No comeback target date has been set, but Wilkinson is unlikely to play again before Christmas.
That means he is effectively ruled out of England's autumn Test matches with the Pacific Islanders, Australia, South Africa and New Zealand.
Wilkinson was set to challenge Leicester's Toby Flood and a fit-again Danny Cipriani for the number 10 shirt under new manager Martin Johnson, but that scenario is now likely to be delayed.
He was carried off midway through the first half at Kingsholm in what was only his fourth match since returning from six months out after shoulder surgery.
"It is a reasonably difficult injury, and it will take a bit of time to come back," added Bates, speaking after Newcastle lost their opening EDF Energy Cup match 25-14 to Newport Gwent Dragons.
"We will have to see how it progresses.
"Jonny plays with 100% effort, and in that respect he is very vulnerable, but he is just the same as everyone else."
Wilkinson is the highest-ever points scorer in Test rugby history and would have scored even more points had he not suffered from an appalling string of injuries since kicking England to World Cup glory in 2003.