Arsène Wenger says there remains “a gap” between Mesut Özil’s ability and his achievements on the pitch as the German gets ready to return to the Arsenal first team. The manager also conceded that Santi Cazorla has had another operation and may not play again this season.

Özil has been the object of much speculation regarding his future at the Emirates, having just 18 months left to run on his current Arsenal contract. At the same time the midfielder is under scrutiny on the pitch, having been accused of going missing in big matches. Wenger, however, believes the 28-year-old, who is back in the squad for the game against Swansea City on Saturday after missing the past three games through illness, still has the desire to improve himself further.

“I think what you want of him is to score goals,” Wenger said. “Certainly we all feel there is still a gap between what he can do [and what he delivers on the pitch]. I think he is moving in the right way but with such a talent maybe you are a little bit unjust because you want always more. You feel there is no limitation in his game and so you are always ‘come on, give us more’. You always have the feeling that they can do more. This is not a frustration, it’s a target. We all are human beings who can improve every day, the problem is that we have to first realise that we want more, ask how can we get more and after that, we have to do it.

“I think Özil has a passion for the game. You do not get the technique he has just by the gift of God. You have to focus on every single pass you make from when you’re a kid to get that touch. So that means you have to have a passion for the game.”

Wenger says he remains “very relaxed” about Özil’s new contract. He also played down remarks, made by the World Cup winner in an interview with the German magazine Kicker, that he would only stay at the club if Wenger extended his own deal, which expires at the end of this season. “I think [the interview] has been a bit misinterpreted,” Wenger said.

“He would like to know what happens on the managerial front of course, but I don’t think that is the main part of his decision. There are many other ingredients in any negotiation and hopefully we will find a conclusion very quickly with him. I’m very relaxed about the situation.”

Wenger also admitted that the Spain international Cazorla, who has been missing from the Arsenal side since injuring an achilles tendon in mid-October, had undergone another operation and was still some way from returning to full fitness. “He had a little procedure, yes, and I have a meeting with the medical people today to see what it was,” Wenger said. “Certainly he will not be available in the next six weeks, that is for sure. I hope he will be back this season but you have to count six weeks preparation and right now he’s not at that level. Let’s hope he can come back in the next three or four weeks on the pitch.”

On the transfer front Wenger rejected out of hand reports that Arsenal had made a £56m bid for the Torino striker Andrea Belotti. The Serie A club’s sporting director, Gianluca Petrachi, said on Sunday that he had turned down an offer of that amount from Arsenal for the Italy international but Wenger denied Arsenal had made a bid, adding “that is what you call today fake news”. He did, however, concede that the right-sided full-back Carl Jenkinson could leave the club, with Crystal Palace the most likely destination.

“It’s a possibility that Carl will move in the next two or three days,” Wenger said. “It’s possible that it’s just a matter of time but I can’t tell you any more because we haven’t come to any conclusion yet.”

When pressed as to whether Palace was the likely destination for Jenkinson he said: “You look well informed.”

Alexis Sánchez, Laurent Koscielny and Petr Cech are, together with Özil, back in the squad having been rested for the FA Cup third-round victory against Preston North End last weekend.