Can cycling affect your soccer performance?

If you do enough of it, sure. Road cycling and MTB XC is mostly about endurance, long rides at moderate power output while soccer is more about short, intense bursts. Cycling can be a good complementary exercise form to boost you stamina, but if you do too much of it you might find that your peak strength begins to suffer. Bike riders are usually fairly lean and stringy guys, while soccer players often have a bit more bulk.