The newly-appointed boss insists the midfielder has got over his injury problems from the start of the season, and is hopeful he can go on to carve out a successful career in Spain
The summer signing from Borussia Dortmund had initially struggled to shake off a recurring knee injury from his time with the German champions, but according to his mentor at international level, the 23-year-old is currently in peak condition.
"Of course I have talked to him about his situation," Avci told AS. "He continues to have confidence that can bring much to Madrid, but obviously he is not going through the most enjoyable spell.
"Still, he feels great, he is in excellent physical condition. Also bear in mind that we are speaking about Madrid, the best team in the world.
"I am sure this season will not end without seeing more of Nuri at Madrid but if something were not to happen, even training in Madrid and being at the club so young is very important."
Sahin has not featured for Real Madrid in 71 days, having played just five matches for the Spanish giants to date, but Avci is still confident his protege will prove his critics wrong over time, and says he will remain part of his plans for the Turkish national team.
"Sahin is 23 and is part of the present and future of Turkey," he continued. "So really, I am not fussed if he plays or not for Madrid. The selection is always open for him.
"Mourinho signed Sahin for five seasons, not five months. He requires patience and [I am sure] he will soon have the role we all want him to have."
Sahin started Turkey's disappointing 2-1 home reverse to Slovakia on Wednesday.