Arsenal star Wilshere has been ruled out of the vital games against San Marino on Friday and Montenegro next Tuesday due to an ankle injury which has sidelined him since the start of March.
But club colleague Oxlade-Chamberlain thinks himself and the other midfielders in Roy Hodgson's England squad can fill the void left by Wilshere.
"The way he has been playing this season has been phenomenal," Oxlade-Chamberlain told Sky Sports News. "He has been outstanding in near enough every game he has played.
"His performance against Brazil was again outstanding. He got man of the match in that game and he deserved it.
"He is a big player for club and for country and I am sure he is going to be a massive part of England's future.
"It is a blow for us to lose him in these two qualifiers. But the other midfielders we have are brilliant players as well. They will fill in and do a brilliant job as well."
Meanwhile, Oxlade-Chamberlain has given his backing to Rio Ferdinand despite the defender having to withdraw from the England squad after an initially surprising return to Hodgson's plans.