The England international has a mild inflammation on his ankle and will miss Wednesday's trip to Bayern Munich as well as Saturday's visit to Swansea City as a precaution.
Wilshere will also sit out England's back-to-back World Cup qualifiers in San Marino and Montenegro but could be back to face Reading at Emirates Stadium on March 30.
Thankfully, the Guardian adds a little bit to the quotes on the official site, saying that it's not the ankle that kept Jack out for over a year, but another ankle, apparently (I guess he has two! Huh!):
Wenger explained: "Jack Wilshere is out. He has an inflamed ankle, the other ankle to [the] one he injured. He will be out for three weeks and will not be available for Munich, Swansea and not for England.
"Hopefully for the Premier League he will miss only one game. After is an international break. We can slowly prepare him."
..."It is more about prevention. The specialist decided he needed it. He has some bone bruising. The last time it deteriorated into a stress fracture. That's what we don't want to happen.