The France international has been heavily linked with a transfer to the Premier League club but LOSC have been immovable in their decision to retain his services.
Newcastle had a fresh approach for the right-back rejected by the French club last week and now his coach has declared that there is nothing the player can do.
"He doesn't really have the choice. The club has made a decision and he has to deal with it," Garcia told French publication Nord Eclair.
"He also knows he has to be good in the game for his future in the French team. I have no worries about him."
The Magpies have been desperate to bolster their squad ahead of their Europa League campaign but have so far also failed in attempts to sign Andy Carroll and Twente's Douglas.