Arsène Wenger has revealed the detail into which Arsenal go to investigate whether injuries could have been prevented, as he prepares to start Joel Campbell at Swansea City on Saturday in response to a pile-up of problems on the right flank.

Alex Oxlade-Chamberlain and Theo Walcott suffered muscle damage in the 3-0 Capital One Cup loss at Sheffield Wednesday on Tuesday and they will be out until after the mid-November international break. Walcott could even be sidelined until December.

It means that Wenger is without six players who can play off the right – Aaron Ramsey, Jack Wilshere, Danny Welbeck and Tomas Rosicky are the others – and so Campbell is poised to make his first Premier League start for the club. Wenger does not want to move Santi Cazorla to the right, and so disrupt his productive central midfield partnership with Francis Coquelin.

Wenger responded to questions about Arsenal’s injury record – he is also without David Ospina and Mikel Arteta – by highlighting the club’s comprehensive approach to fitness. His conclusion was that it simply had to be accepted that some players were more susceptible than others.

“We sit down together and analyse exactly the workload of the players,” Wenger said. “In the last six weeks, for example, we know exactly the percentage of work each player has done – what sort of exercise he has done, the intensity of his work every day, how much he has sprinted. We put it all together to see if we made a mistake.

“I don’t want to put that label [of players being injury-prone] on them. It’s like in life – why does he catch the flu and him not? You have to accept that medically, we are not all even. We have brought other fitness coaches in and we individualise a programme for the players. But there are plenty of things that you can’t master – the competition, players may have a virus and, as well, things during the game. I trust my medical staff to do well and my coaching staff to do the fitness planning very well. We have some players who are more injury-prone than others but we are well organised on that front.”

Campbell signed from Saprissa in 2011 and he has spent almost all of his Arsenal career out on loan. But Wenger kept him at the club at the start of this season, as he felt that he could also provide cover at centre-forward, and he sees this as Campbell’s defining moment.

“It is now or never for him with us,” Wenger said. “You go one time out, two times out – after that, you don’t know any more if you belong to the club or not. What is important for me is the next game. Football, and life as well, is play the next game like it was your last.

“There is a challenge for the players who come in to show their quality and, at the end, you can find yourself with a bigger squad. That is what happened with Coquelin and Bellerín last season. Campbell’s attitude is absolutely outstanding.”

Wenger’s theme was the seizing of the moment, and he urged Remi Garde, who was his joint-first signing at Arsenal in 1996, together with Patrick Vieira, to join Aston Villa as the manager. Garde, the former Lyon manager, has held talks with Randy Lerner, the Villa chairman, and he is the clear frontrunner to succeed Tim Sherwood. But he wants to take the assistants Bruno Genesio and Gerald Baticle from Lyon and that has proved problematic.

“Remi should just take it,” Wenger said. “You do not get 20 opportunities to come to England and, at the moment in Europe, you find 250 managers who want to come to England.”