Wilshere out for three months
Wilshere was left in a heap under a challenge from United youngster Paddy McNair as Louis van Gaal's side ran out 2-1 winners at the Emirates Stadium last weekend.
And the England midfielder is now set for another extended spell on the sidelines, having gone under the knife to mend damaged ligaments in his left ankle.
The 22-year-old has suffered badly with injuries since making his debut in September 2008, especially ankle issues, which forced him out of the entire 2011-12 season.
A broken foot in March earlier this year limited Wilshere's involvement in Arsenal's run-in to last season, indeed he only made one appearance - as a substitute in the FA Cup final - before the term was through.
Two appearances in England's World Cup campaign and a generally positive start to 2014-15 suggested he could finally fulfill his potential, though that is now set to be checked again.
A club statement read: "Jack will now commence his injury rehabilitation programme with the Arsenal medical team.
"Everyone at the club wishes Jack a speedy recovery and look forward to seeing him back on the pitch as soon as possible."
The news comes as a major blow to Arsene Wenger, who is also set to add Mikel Arteta to his lengthy injury list after the Spaniard limped out of Wednesday's UEFA Champions League win over Borussia Dortmund.