Welsh global, Aaron Ramsey, is due for a scan after suffering a hamstring strain in the tie.
Fighting back to lose by a 3-4 scoreline with Liverpool leading 1-4 at one stage, it was a hard afternoon for Arsenal supporters to bear with the loss coming on the back of a frustrating summer in the transfer window.
It means Iwobi will now miss Saturday's trip to the King Power to face champions Leicester City and the trip to Vicarage Road to take on Watford the following week before the upcoming worldwide break.
The news will come as a blow as Iwobi has established himself as an important part of the first team squad over the past 12 months but he's now joined Aaron Ramsey on the sidelines after the Welshman was also ruled out for a month with a hamstring problem. The latter was to replace Ramsey on the hour.
Laurent Koscielny is not match fit after returning to training just a week prior to the start of the season, and the manager will be wary of rushing him and risking another injury.
Despite statement's to the opposite pre-game, Wenger admitted his side were "not ready physically" in the aftermath of the Liverpool defeat.
In many ways, yesterday's opening day game against Liverpool couldn't have gone any worse with the Gunners capitulating in the second-half like so many other times in the past five years or so.
Keown, who won three Premier League titles with the Gunners, also believes frontman Olivier Giroud is under-rated after impressing for France at Euro 2016.