Wilshere did not play for the entirety of the 2011-12 season due to an ankle injury and also missed out on Euro 2012 as a result.
While the club say he is recovering well from that particular problem, the process of rehabilitation "has seen a long-standing slight issue with his patella tendon in his left knee flare up."
Wilshere will now undergo surgery in Sweden in the coming days and Arsenal say the news is not expected to have a major impact on his continuing recovery.
In April, Arsene Wenger raised doubts as to whether Wilshere would be fit for the start of the 2012-13 season and said he did not want the 20-year-old to be considered for the Olympics.
Wenger said: "I do not want to set the Olympics as a target because I do not know whether Jack will be fit to start at the beginning of the season."