By Arsenal correspondent Tony Hughes 

Olivier Giroud was substituted early in Arsenal’s Premier League defeat to Chelsea partly because he was suffering from an ankle injury.

Manager Arsene Wenger revealed afterwards that the Frenchman did not train on Saturday because he sustained a knock to his ankle.

Giroud was passed fit to start the 1-0 defeat to Chelsea on Sunday but was sacrificed after 21 minutes following the dismissal of Per Mertesacker to make way for another centre-back, Gabriel.

Arsenal’s 18-goal leading scorer was clearly furious at the decision, making clear his disapproval by shaking his head as he trudged off the pitch.

Wenger said his shock substitution was partly motivated by Giroud’s ankle problem going into the match and also his desire to have faster players on the counter-attack against a team with a one-man advantage.

Asked about taking off Giroud at his pos-match media conference, Wenger said: “You want to make a poll for every decision to see who does what?

“I made the decision and for me it was quite normal. We had to go for long distances and we needed pace to go from one goal to the other. We knew we had to drop deeper and use pace to get forward.”

Decision maker: Wenger defended his surprise substitution of leading scorer Giroud

Decision maker: Wenger defended his surprise substitution of leading scorer Giroud

The Arsenal manager was also concerned about Giroud’s ankle even though he was convinced the striker was fit to start.

“I think yes, but it was a bit in my mind if he gets injured, with his ankle. He was a doubt, he didn’t practice yesterday and today we declared him fit.

“It was on my mind. But I had to change a player and I thought that was the most rational decision with all the factors.”

Giroud is likely to be wrapped in cotton wool ahead of the Gunners’ next match, a home FA Cup clash against Burnley next Saturday.