Arsène Wenger has expressed his "surprise" at the England Under-21 manager, Stuart Pearce, for questioning the professionalism of Jack Wilshere after the 18-year-old was arrested outside a nightclub last month. Wenger maintains the player "has not done a lot wrong".

Wilshere was arrested and bailed on 29 August after a fracas in the early hours in central London. Pearce then dropped him for the Under-21s match against Portugal, saying the player lacked focus and had "taken his eye off the ball".

"I was surprised and I don't think it needs any more comment," said Wenger of Pearce's remarks. "Jack is quite focused on training and he wants to do well."

The Arsenal manager suggested that he understood what could have caused the player to become embroiled in the incident that led to two people suffering injuries and police arresting three men in addition to Wilshere. The police investigation is on-going. "From what I've heard Jack hasn't done a lot wrong," said Wenger. "If I go out with you [and you have a problem], do you want me to run away? If I have a friend with me and I'm in trouble I prefer that he stays."

Wenger also suggested that an involvement by Wilshere may be viewed more severely by the public because of his profession. "Sometimes for me a guy who goes out is not a footballer only. He's a friend or a man who is there – why is it just the footballer who is completely different in that kind of situation?" said Wenger, "If I go out with you and you have a problem with somebody else I am not a footballer, I am somebody who is just trying to sort something out."

who admitted that "ideally, footballers should be at home in bed at 3am", but added that "none of us were angels when we were 20 ... we all made mistakes." He did, however, warn that Wilshere is unlikely to fulfil his potential if he does not learn from the incident. "You don't make a career at the top level if you don't know how to behave – it's impossible."

Wilshere is in contention for tomorrow's match against Bolton, where he spent four months on loan last season, making, according to Wenger, important progress. "I am grateful that Bolton played him because that helped him develop," said Wenger. "Owen Coyle did a great job. He was already a very gifted player when he went to Bolton but he continued his development there. He took some responsibility and confidence and also grew physically. He's only 18, there is a lot more to come from him."

The Frenchman also praised goalkeeper Manuel Almunia for retaining his focus in August despite knowing that Arsenal were trying to sign Fulham's Mark Schwarzer. "When you play for Arsenal you have to deal with competition and he has done that," said Wenger. "I give a lot of credit to Almunia and [Lukasz] Fabianski because during all this period they have dealt very well with the pressure and the uncertainty and now they should be even better because they know they will play."

Arsenal will be without Theo Walcott for up to six weeks following the ankle injury suffered by the winger when playing for England against Switzerland on Tuesday. Walcott's career has frequently been interrupted by injuries but Wenger rejected any notion that he is an exceptionally fragile player. "It was a bad tackle, it could happen to anybody. I'm more worried about the quality of the tackling in the modern game."