Koscielny shocked Arsenal fans last week when he refused to join the club on their pre-season tour of the USA.
The Frenchman has been at the club for over nine years.
And with him turning 34 not long after the season kicks off, it was generally assumed that he would see his career out in north London.
However, Arsenal’s club captain is insisting he be sold in this transfer window, with the player thought to be unhappy about the direction the team are headed.
“I don’t understand how we have got to this situation”
Koscielny’s decision has come in for criticism from a number of people, with Gunners legend Ian Wright warning him he was “destroying his legacy”.
But fellow countryman and ex-team mate Giroud has leapt to the centre-back’s defence, insisting people need to think about his feelings too.
“He’s been playing for Arsenal for nine years; he’s been the skipper for so many years – very respectful, very professional, always the best example for the young players.
“The club gave him the opportunity to play at Arsenal, and it was a big, big opportunity for him to show his quality in the Premier League.
“I think he has always been grateful about that and respectful to the club. I don’t understand how we have got to this situation.
“I feel very sad for him because he’s a great person and the media wants to give a bad image of him.
“I’m not at the club, I don’t know what really happened – but one thing for sure is Lolo is very hurt by what’s happening and he’s an emotional person.”
Arsenal are understood to have put an £8.8m price tag on Koscielny’s head.
Ligue 1 sides Bordeaux, Rennes and Lyon are all keen on bringing him back to France.
But despite his age, the Gunners refuse to be drawn in to accepting a lower offer for him.