He has made just 16 appearances in all competitions for the French champions and has not featured in Ligue 1 since December 2016.
"I speak with all my players, so also with Krychowiak," Unai Emery said at a news conference.
"He has a lot of competition in his position at the moment. Adrien Rabiot plays in his position now that Thiago Motta is not there. It is a very difficult position.
"Krychowiak will not be part of the squad for Sunday's game, but he will be with the reserves. It is a matter of competition. He has asked to play with the reserves.
"He can still play with the first team in the upcoming weeks. He has to make sure he is ready and that is why he will play with the reserves now to gain match rhythm."
New arrival Goncalo Guedes, meanwhile, will be part of the matchday squad, but Emery has made it clear the winger is unlikely to start and will have to be patient.
"Goncalo is a young player and he will have to be patient," Emery continued.
"He has been training really well and is showing a lot of desire. He has to prepare in order to be ready each time he gets some playing time.
"He will be part of the squad. I am very happy with him. Expectations at PSG are even higher than at Benfica. He has to keep making progress."