Arsenal bring Per Mertesacker back for likely aerial duel with Andy Carroll

Arsène Wenger expects giant centre-half to be fit and in the trenches for West Ham bombardment

Arsène Wenger hopes he has Per Mertesacker ready for the aerial challenge of West Ham United this evening. Arsenal travel to Upton Park where they are likely to face a returning Andy Carroll.

Mertesacker has started the season well before suffering from a virus which has afflicted the Arsenal squad. His heading ability would certainly be useful if he recovers.

"He has made a big leap," Wenger said of Mertesacker's form this season, "and he came back very fit and has improved his fitness a lot. His mobility. He looks very sharp on the first day that he came back. He lost some weight. And that helps of course."

The Arsenal manager is an admirer of Carroll, who should make his second West Ham start today. "I rate him, and don't l think we have seen the best of him until now," Wenger said. "Since I have seen him at West Ham, he looks back to the Carroll we have seen at Newcastle, that means with less pressure."

Wenger does not believe that today's threat is purely aerial, though. "West Ham have a good mixture," he said. "They can come from midfield. [Mohamed] Diame can make a difference. [Kevin] Nolan is always dangerous on the second ball. And [Matt] Jarvis is a technical player."

"You know your players need to be 100 per cent focused. One mistake - you can have a virtual domination and lose the game. It's a concentration challenge as well." As well as a late decision at centre-back, Wenger is still searching for his favoured centre-forward. While no-one has taken over Robin van Persie's role, Wenger said the newly collegial approach to goal-scoring was a good thing.

Van Persie last season scored 30 of Arsenal's 74 Premier League goals. This year the burden is being shared, after his move to Manchester United. "We have no choice," explained Wenger, "as we had one that scored so many." Losing Van Persie meant losing Van Persie-dependence too and Wenger said that this was healthier for the team, revealing just how desperate his players were last year to be led out by their captain, the talismanic Dutch striker.

"Because when Van Persie was injured of course it is not only that you cannot score goals any more," Wenger said. "It is the psychological consequences on the morale of the team. 'Does Van Persie play on Saturday?' Players ask you already, does Van Persie play on Saturday or not, when he has two or three days out."

Wenger signed two strikers from the continent in the hope of replacing Van Persie's 30 goals, but admitted they might not quite make up the required numbers. "We bought Lukas Podolski [who had scored] 20 [league goals last season] and [Olivier] Giroud 20, that is 40," Wenger said. "But it unfortunately has not worked out like that."

Giroud is yet to score in the Premier League, with Gervinho rather surprisingly becoming the main centre-forward so far. Wenger hopes that the other wide and creative players will help to contribute. "We hope always that [Theo] Walcott can improve his number of goals. Gervinho as well," he said "[Santi] Cazorla will get a few. He gets in good positions and does not always finish. But he looks like he can score goals."