Neymar, 34, hasn’t played for Brazil since their 2-0 defeat to Uruguay in October 2023, in which he suffered a severe knee injury.
The forward has been included in Ancelotti’s preliminary 55-man squad for this summer’s World Cup, however.
With the biggest tournament in football just weeks away, Ancelotti is weighing whether to include Neymar in his final squad or not.
"When you have to choose, you have to consider many things," Ancelotti told Reuters.
"Neymar is an important player for this country because of the talent he has always shown. But he has had problems and is working hard to recover.
“He has improved a lot recently and is playing regularly. It is, obviously, not such an easy decision for me. We have to weigh up the pros and cons carefully."
Ancelotti is prioritising the dressing room atmosphere ahead of the World Cup, adding: "I know full well that Neymar is much loved, not only by the public but also by the players,"
"This is also a factor, because we have to consider the atmosphere that will surround Neymar's call-up. It's not as if I'm going to drop a bombshell in the dressing room. He's very well-liked, he's very much loved.
“I think it's normal for the players to express their opinion. I'm grateful to everyone who has given me advice; I thank you all. But ultimately, the right person to make this decision, the one best placed to do so, is me."