Arsène Wenger remains worried about Jack Wilshere's fitness and admits the midfielder needs to be carefully managed given his continuing ankle problem.

Wilshere will be assessed before Saturday's trip to Crystal Palace after being substituted during the second half of the midweek Champions League defeat to Borussia Dortmund after jarring his ankle.

The Arsenal manager explained that managing a condition that can flare up when he plays is still a concern.

"It's difficult for us to find the right rhythm for him," Wenger said. "Before I played him always and people say I overplayed him. Now I try to be a bit more cautious. It's difficult because his ankle is up and down a little bit.

"He's getting better but it's still inflamed sometimes and responds sometimes to games. But after that it goes down again and is normal. I think he will go through this period of stabilisation. It's going upwards but sometimes you wonder do I take a gamble or not?" Wilshere had a fitness test on Friday, to establish whether or not he can play a part at Selhurst Park on Saturday.

This would appear to be a reasonable time to rest the England man, as Arsenal have a Capital One Cup match with Chelsea on Tuesday night in which Wenger is expected to field a mixed team of regulars and reserves. After that they face a heavyweight week with games against Liverpool, Borussia Dortmund and Manchester United.

Wilshere lost more than a season to injury in the past, but although he has not yet regained total and reliable fitness, Wenger is not concerned that this is a problem that will need long-term management. He is hopeful that it will be resolved. "He's 22 years old. He needs competition. I do what the medical people recommend with him because I am not a specialist. They are quite positive about him."

The midfielder Mathieu Flamini will be available having missed the Dortmund game as a precaution after suffering a mild concussion in the 4-1 win over Norwich.

Wenger revealed the £42.5m club-record signing Mesut Özil had played on Tuesday night despite suffering from a virus, which went some way to explain a subdued performance from the German playmaker.

"He was sick before the game and he was not at his best on the night," Wenger added. "He said he was all right, but in the two days before he had a virus and you could see that physically he was not at his best."

Wenger had some sympathy for Ian Holloway, who left Palace by mutual consent this week having failed to win a league match since getting his side promoted to the Premier League. "I find it very quick and very early to separate with Ian Holloway. For me, he has exceptional talent to manage a football team," Wenger said.