Arsène Wenger will make wholesale changes to his regular lineup for the EFL Cup quarter-final at home to Southampton on Wednesday night while he has been reassured that Olivier Giroud’s muscular injury is nothing serious.

Giroud came on as a substitute in the 3-1 win against Bournemouth at the Emirates Stadium on Sunday and he felt something pull after what was his first involvement. Wenger thought, immediately afterwards, that Giroud had hurt his hamstring but it is the groin that has sustained the damage.

Wenger, however, has described the problem as only “slight” and, although Giroud will not play against Southampton, he has not yet been ruled out of the Premier League fixture at West Ham United on Saturday.

Lucas Pérez has recovered quicker than expected from the ankle injury he sustained in the previous round of the EFL Cup – the 2-0 home win against Reading on 25 October – and the striker is in line to feature against Southampton.

Wenger has used his squad players in both rounds of the competition so far – against Nottingham Forest, when the team won 4-0 away from home, and Reading – and he will not deviate from the policy for Southampton’s visit.

Emi Martínez will once again start in goal while Wenger will change the entire back four from the Bournemouth game. Mathieu Debuchy is still awaiting the results of a scan on the hamstring injury he sustained against Bournemouth – the fear is that the damage is serious – while Laurent Koscielny, Shkodran Mustafi and Nacho Monreal will be rested.

Wenger is expected to start with Carl Jenkinson, Gabriel Paulista, Rob Holding and Kieran Gibbs in defence. The manager will also rest his three most potent attacking players, on current form – Mesut Özil, Theo Walcott and Alexis Sánchez. He has decisions to make across midfield, where he will chose from Mohamed Elneny, Francis Coquelin, Alex Oxlade‑Chamberlain, Alex Iwobi, Aaron Ramsey, Granit Xhaka, Jeff Reine‑Adélaïde and Ainsley Maitland-Niles.

“We will have a mixture of youth and experience but still 90% of a first-team squad,” Wenger said. “Debuchy is out and Giroud has a slight problem – he’s out, too. Pérez is in the squad and Jenkinson will play. I rested Carl completely against Bournemouth because he had played in two big games [against Manchester United and Paris St-Germain] and I felt he needed a breather [having only recently returned from a nine-month injury lay-off]. Sometimes, mentally, three games in a week demands a lot. Carl’s back in and we’ll put Gabriel in the centre.”

Arsenal v Southampton EFL Cup quarter-final, 7.45pm