Wilkinson travelled with Newcastle on their 10-day tour of Japan, but he complained of sickness and was admitted to a hospital in Tokyo where tests revealed an appendix problem.
The No 10 has not had the appendix removed, and his condition will continue to be monitored, although he definitely misses today's game against Toyota Verblitz, near Nagoya.
He had hoped to play a part on the Falcons' pre-season trip, having recovered from another "stinger" injury to his neck and shoulder sustained during the Lions' second Test defeat against New Zealand in Wellington two months ago.
Newcastle will launch their Guinness Premiership campaign away to Sale Sharks on 2 September.
The England forward Martin Corry insists the domestic game does not have too much to learn from Graham Henry's All Blacks.
Corry, captain in the 2005 Six Nations when Jonny Wilkinson and Jason Robinson were injured, believes England's top clubs should have the courage of their own convictions rather than scouring the wreckage of the Lions tour for clues.
And despite the recent appointment of the Australian Pat Howard as head coach of his club, Leicester Tigers, Corry is adamant any rush for all things Antipodean is not necessarily the best way forward.
Corry said: "If you start copying sides and saying this is what New Zealand do, then you are always going to be playing catch-up."Reuse content