He also disclosed that the Gunners manager, Unai Emery will not feature play maker, Mesut Ozil against Huddersfield.
Meanwhile the Spaniard warned that the diagnosis for Rob Holding's knee injury "is not good". Emery said he will make a decision on whether Ozil can feature on Saturday based on whether he can join in the full team training session on Friday.
"He gives us experience, quality, personality", Emery added. You've got to take the positives from somewhere and that's the job of the management to say: "'Right, there were certain things we can take positives from, then build on it'".
This morning he worked with the physiotherapist on the pitch, running and touching the ball.
Ozil, who was dropped for the game, has since been suffering back spasms which ruled him out of the Europa League clash against Vorskla Poltava, Sunday's win over Tottenham and Wednesday night's 2-2 draw at Manchester United.
We are waiting. The club can give us communication about this.
"We are going to wait for what the doctor tells us but it is maybe a big injury".
Koscielny's return seems to come in the nick of time, as Arsenal face setbacks with fresh injuries to Rob Holding and Aaron Ramsey - with the former suffering from what is expected to be a long layoff after limping off against United.
Arsenal host Huddersfield at The Emirates on Saturday as they look to extend their excellent unbeaten run. He's playing for the under-23s with a good feeling. "We need every player and we need also for him to train with us".