The Qatari-owned outfit acquired the Argentine from Palermo last summer for a reported fee of €40 million and he has played a key role in the club's fine form in Ligue 1 this season.
However, Ancelotti admitted that he could drop Pastore to the bench for Saturday night's clash with Lyon, claiming that PSG would fare just fine without the 22-year-old attacking midfielder.
"I do not know if Pastore will play from the first minute because he needs to work on his fitness," the former AC Milan boss is quoted as saying by Maxifoot.fr.
"But he was important against Montpellier [last weekend]. He has great qualities and is a major player.
"Conversely, he is not indispensable. No player is indispensable."
Pastore, who has been capped 13 times by his country, has contributed seven goals in 19 starts in Ligue 1 for PSG.
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