Rohr is mulling the decision, because they are stil in pre-season training with their Chinese clubs.
Also, the timing of the friendly games coincides with when the league will resume in China.
Rohr wants Mikel Obi and Ighalo to concentrate on their club especially early into the season, but he is yet to fully make up his mind over excluding them from the squad for the games against Serbia and later Poland.
If the duo are eventually left out, Rohr is considering handing a recall to striker Brown Ideye who recently signed for LaLiga side Malaga and netted his first goal last weekend in their loss to Valencia.
In-form ex Inter-Milan midfielder Joel Obi is also under consideration.