Arsenal are braced to be without their captain, Mikel Arteta, for the games against Everton and Besiktas after the Spanish midfielder suffered a badly sprained ankle in a tackle with Demba Ba in Tuesday’s goalless Champions League qualifying tie in Turkey.

The midfielder’s absence at his previous club on Saturday can be offset by Mathieu Flamini’s return to the starting lineup, although Arsène Wenger’s side will be depleted for next week’s return leg against Besiktas, with Aaron Ramsey also suspended for the game. The extent of Arteta’s injury will become clearer once scan results have been assessed on Thursday but the club expect him to be out for at least two weeks and do not anticipate him featuring until after next month’s international break.

Wenger had considered strengthening his central midfield this summer, and interest was registered in Real Madrid’s Sami Khedira and the Sporting Lisbon player William Carvalho. But the Frenchman has since preferred to look elsewhere. A deal should be struck with Olympiakos for their defender Kostas Manolas for around £6m leaving the current squad – supplemented by the returning World Cup-winning trio of Mesut Özil, Per Mertesacker and Lukas Podolski – to take up the slack.

“It’ll be good having [the Germans] back, and it will make our squad stronger,” said the midfielder Jack Wilshere. “We know it’s not going to be an easy game in the return leg, and we can’t take anything for granted. We worked really hard last year to get into the top four, we always want to get in the Champions League, to attract players who want to play Champions League. We’ve got players at the club who have to play in that competition, so we know it’s a big game and we have to treat it like that. But we’ve got Everton first and it’s never easy going there.”

There is confidence that Besiktas can be overcome in next week’s return. The goalless draw at the Ataturk Stadium left the tie in the balance, and Besiktas won at Feyenoord in the previous qualifying round, but Arsenal are convinced they will reach the group stage for a 17th consecutive season.

“It’s something everyone wants to play in, especially at a club like Arsenal,” said Alex Oxlade-Chamberlain, who struck a post late on at the Ataturk. “We almost expect ourselves to qualify. It’s something we worked extremely hard for at the end of last season, to get ourselves into this position, and we don’t want to give it away at this stage. It is massive for us as a club, and as players and the fans. I’m sure you’ll see next week how much everyone wants to be a part of this competition.

“We definitely have to have confidence in ourselves to come through this test. Besiktas are a quality side and it’s not going to be easy at all. They’ll fancy their chances as well and a goalless draw does make our task that little bit harder back at the Emirates Stadium. But I’m confident, if we approach it in the right way and match them physically and competitively, that the technical side of our game will come through.”

The Besiktas coach, Slaven Bilic, is likely to be suspended for next week’s game after being sent to the stands late on in Istanbul for continually berating the Serbian referee. The former Croatia manager, who apologised after the match for his actions, will serve an automatic one-match ban – sitting in the stand with no access to the dressing room or team-talks at the stadium – which may yet be extended when the Uefa disciplinary committee meets early next week.

Uefa will also discuss the incident in which a bottle was thrown from the stands at Wenger after the final whistle.