Wilkinson has trained all week, yet it now looks as though he will not feature until Newcastle entertain Borders in the European Challenge Cup on Sunday week.
"He is fine, but his adductor is just a little bit sore. There haven't been any complications or anything like that, it is just part of the recovery process and he isn't far away," said Falcons rugby director Rob Andrew.
"In hindsight, we probably jumped the gun a little bit by saying he might play against Worcester last weekend, but everything we said in the lead-up to that game was true at the time we said it.
"He had been looking extremely sharp in the training he'd been doing with our physio Marten Brewer and our fitness coach Steve Black, and we thought on that basis that he had a chance for the Worcester game.
"The problem was that we hadn't had a chance to get him training with the team due to playing Leeds on the Tuesday, and then the snow in Newcastle which forced us to cancel sessions late in the week, so when we weighed it up on the day of the game we couldn't be 100% certain that including him was the best option.
"We've taken on board all the medical and clinical advice, and with these things you often just get a gut feeling as well, so we thought it would be stupid to risk him this week and throw him straight in when we could let him have another full week of training and then look at the Borders game to see if he is back in the mix.
"He has trained more with the team this week, and has done every team session apart from the full contact stuff on Wednesday afternoon, but we just want to give him another week and see where we are from there."
Fly-half Wilkinson has not played for England since the 2003 World Cup final triumph in Sydney because of a catalogue of injury setbacks, and his last Newcastle start came against London Irish in mid-November.