I incorporated running/jogging/fast walking (whatever you want to call it) into my off-season plan this year and in hindsight, this is what I would suggest:

Be sure you have a pair of shoes that fit you well. I was having some knee pain when I first started. A new pair of sneaks fixed this. I would also highly suggest following a training plan of some sort. I did Couch to 5k and it kept me from pushing too much too soon. As a noobie, I would also start running on flat terrain or a treadmill. Finally, don't stress about the time. Running is great because you can get in a fast workout with intensity in a fraction of the time it takes to ride. Be sure to stretch and let any pain or discomfort be your limiter. Have fun!