Hello,
I am a runner too and worried about injuries when I started riding 3 months ago. Other than a sore butt, I never experienced any problems. If you follow the recommendations mentioned above like building the base mileage, increasing weekly by no more than 10%, making sure the bike fits you, you should not have problems. Riding is much easier on the body than running.

By the way, my husband runs and rides too but we have a good run or ride if we manage to finish together without an argument. Other couples I spoke to report the same. How does it work for you?

Monica