Jonny Wilkinson remains sidelined for Newcastle's clash with Wasps on Sunday but is expected to be available a week later.
An ankle injury has prevented England fly-half Wilkinson from playing since the 15-6 World Cup defeat by South Africa nearly five weeks ago.
His Newcastle and England team mate Toby Flood will also miss the Guinness Premiership showdown at Wasps after rolling his ankle.
Both players are expected to be fit for the EDF Energy Cup clash against the same opposition a week on Saturday.
Newcastle director of rugby John Fletcher said: 'Jonny's ankle hasn't settled as much as we thought it would. He's had an injection this week to get the inflammation down a bit. He was very close to playing this weekend and did most of our training throughout the week. He will resume full training on Monday and will be in contention for selection for the following game.
'Toby being out is a frustration as well because he'd recovered from his previous injury and then just rolled his ankle in training on Monday.'
Newcastle have named a starting line-up featuring 14 English players and 10 academy graduates for Sunday's trip to Wycombe.
Fletcher said: 'We are a regional side representing the north-east and Cumbria, and we want to give opportunities to good regional players.
'I'm a massive believer in the fact that domestic competitions have a responsibility to produce players for the national team.
'The easiest thing to do would be to go and buy a team full of South Africans or Pacific Islanders who can play 22 Premiership games a season.
'That would be a decent team, but what benefit would there be to English rugby or north-east rugby by doing that?
'First and foremost I'm a Geordie, but secondly I'm English, and we all have a duty to support the English game.
England Under-18 head coach John Fletcher insists his young side will be better for the experience after beating Italy in the bronze final to round out their 2015 Rugby Europe U18 Championship campaign in style.