Arsenal's armband wars

It seemed an odd decision by Wenger, akin to promoting the school's problem child to head boy in an effort to channel his energy with extra responsibility.

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Gilberto admitted he was shocked and "upset" to read the story on the club's official website and Wenger was forced to explain his thinking in a meeting with the Brazil midfielder.

The manager appeared uncharacteristically sensitive on the subject when it was raised in the build-up to the Champions League qualifier against Sparta Prague here tonight.

Gallas developed a reputation as a serial moaner and a disruptive dressing-room influence during his time at Chelsea and it was one of the reasons Jose Mourinho agreed to let him join Arsenal a year ago.

Wenger said: "Gallas has to be an example everywhere — not just on the pitch — and I have spoken to him about that. I don't know how he behaved at Chelsea but this year he is a very positive influence.

"I respect Gilberto a lot. He did a good job last year. We have had an eye-to-eye meeting and I told him what I wanted to tell him and that's it.

"He was not in the group last week and that's why what happened happened. I've nothing more to say. I cannot justify every small decision and explain it to everybody."

Gilberto started his pre-season late after captaining Brazil in the Copa America but he was an impressive stand-in Arsenal skipper for much of last season.

Mentally strong and calm, he was seen by many as the natural successor to Thierry Henry and had expected to inherit the job full time when Henry left for Barcelona.

Gallas, in contrast, grumbled his way out of Chelsea last year, often complaining publicly about being forced to play out of position and unhappy that he was not offered the contract he felt he deserved.

His attitude did not appear to have changed this summer when he criticised Arsenal on his website for failing replace Henry with bigname signings.

But he admits his new role brings new demands and promised to change.

"I'm aware that being club captain is not only a job on the pitch but also away from it," said 29-year-old Gallas. "I have to give a good example in everything I do and I will do that. You will see a new William Gallas this year.

"When I came to Arsenal the one thing I wanted to do was win. Last year wasn't easy. We had too many injuries but everything's changed. We will do something this season."

Wenger will hope his controversial decision will inspire a response from Gallas similar to the one from Patrick Vieira when the captaincy helped the midfielder overcome his own disciplinary problems to mature into one of Arsenal's finest players.

The Gunners flew to the Czech Republic without Gilberto and injured quartet Eduardo da Silva, Abou Diaby, Denilson and Emmanuel Adebayor.

Sparta Prague include Tomas Repka in their squad. The former West Ham cult hero is available after a domestic suspension but the Czech champions are expected to start without him.

Wenger said: "This is a vital game. We want to be in the group stage and usually it's nobody much to stop you getting inside on to the red carpet but Sparta Prague are a very strong team."

There will be extra spice for Czech international Tomas Rosicky, who returns to the club where he started his career keen to impress Arsenal fans after an indifferent first season at the club.

"I have mixed feelings," said Rosicky. "I grew up at Sparta and the club prepared me for my career and now I am standing on the other side. It will be strange but I feel more at home at the Emirates Stadium at the moment."

SPARTA PRAGUE (4-4-2): Postulka; Pospech, Kadlec, Brezinski, Kladrubski; Abraham, Husek, Kisel, Limperski; Kulic, Dosek.

ARSENAL (4-5-1): Lehmann; Sagna, Toure, Gallas, Clichy; Eboue, Hleb, Flamini, Fabregas, Rosicky; Van Persie. Referee: Luis Medina Cantalejo (Sp).

TV: Setanta Sports 1, 7.15pm (kick-off 7.45).