Bony limped off just before half-time in the 1-0 Group A loss, having pulled up clutching the back of his right leg chasing a long ball.
Swansea boss Michael Laudrup said: "It could be quite a serious one. We'll have to wait two or three days until we get a scan but unfortunately we are talking several weeks.
"It is a blow but that's how it is. You have to accept it and when you have a lot of games this is a possibility.
"Let's see what happens with Michu in the next week or so."
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