Arsene Wenger has major injury problems for Arsenal's Champions League clash with Porto tomorrow after five players were ruled out of the last-16 match.

Manuel Almunia, William Gallas, Alex Song, Eduardo and Andrey Arshavin have all been sidelined and did not fly with the squad to Portugal today, leaving Arsenal as underdogs on the sports bet markets.

Manager Wenger is already without long-term absentees Robin Van Persie, Kieran Gibbs and Johan Djourou, meaning the strength of his squad will be severely tested in light of his decision not to spend the £40million available in last month's transfer window.

The Gallas injury is a worry for Wenger given Vermaelen admitted this week that he is playing through the pain barrier after injuring his leg against Aston Villa last month.

Lukasz Fabianski, who has had just five games this season, should deputise in goal for Almunia while Denilson is set to take Song's holding midfield role.