Arsenal are braced to be without their captain, Cesc Fábregas, when they travel to Ukraine tomorrow with the Spain international unlikely to be risked after complaining of a tight hamstring during the narrow victory over West Ham United on Saturday.

Fábregas was ruled out for a month earlier in the campaign after pulling a hamstring in the draw at Sunderland and only returned in the recent 5-1 Champions League group game success against Shakhtar Donetsk at the Emirates. His absence from the return fixture on Wednesday is unexpected with the team comfortably placed at the top of their section, and with one eye on the visit of Newcastle United to north London on Sunday, though it could yet be compounded by that of Alex Song.

Arsenal's match winner against West Ham suffered a kick to his calf towards the end of that victory and departed the stadium with heavy strapping on his leg. The Cameroonian will be assessed again tomorow before the squad depart for Donetsk, with greater emphasis inevitably to be placed on Jack Wilshere in their anticipated absence.

The 18-year-old signed a new five-year contract today worth in the region of £50,000-a-week, well‑deserved reward for the eye-catching form to date this term that has earned him elevation to the full England squad.

"At still only 18 years of age, there is still so much more to come from him, and we're all excited by the fact that Jack will be an Arsenal player for years to come," said Arsène Wenger, who still hopes to secure his young goalkeeper Wojciech Szczesny to a similar long-term deal. "Jack is a fantastic footballer with a huge amount of potential, and we have all seen with his performances so far that he is a very gifted player who could be an extremely influential player at the top level of the game."

Wilshere revealed on Twitter that he was "buzzing" to have signed the contract and described Arsenal as his "second home".

"I've got a long way to go before I can become the player I dream of becoming, and I'm sure I'll keep making the odd mistake," said the midfielder, who will return from a three-match domestic ban on Sunday following his sending off against Birmingham City.

"But it is a massive help for me having a special manager like Wenger and so many quality team-mates around me. I believe there is a lot more to come from me."

Both Nicklas Bendtner and Theo Walcott are expected to start in Donetsk, where victory will secure Arsenal qualification to the knock-out phase and, in effect, the leadership of Group H.The Londoners' midfield ranks could be bolstered further by the return of Aaron Ramsey to full training, most likely on Friday, though Wenger does not envisage the Wales international being ready for a first-team appearance for some weeks to come. Ramsey broke his leg at Stoke City in February and has been stepping up his rehabilitation in recent weeks.

"Aaron should be in full training next Friday," said Wenger. "But then you have to give him at least one month's competition with the reserve team."