It depends on how Bike Set up how you load your muscles. If your seat is set far forward you will load your quads more. Automatically we use our quads more by pushing down on the pedals. Also we don’t extend the legs on the bike, so the motion is still different to running.
I used to be able to knock out my fastest 5kms on minimal running and only a bit of intervals plus a lot of cycling.
When I ran more I didn’t run as well until I dropped the volume of the riding, as my lower back and hips were getting stiff from my cycling position.
However, I don’t think you are going to do any damage by riding and not running. You will notice a little difference in strength (run vs cycling) and also from conditioning. When you start running it feels a little harder, but the flow comes back easier.
This year I was tore my calf muscle and did a mix of aqua jogging and cycling. I was only doing 60 minutes or so hard on a windtrainer, but when I could run again after 2 weeks was back to 130km+.
At the end of the day riding is going to help you stay fitad sane and then you will be able to get back into form easier.