Enrique, thank you for posting on our forums.
You’re wise to think about this, as it would not be a good idea to try and pick up your running where you “should” be in your plan. Especially if you have not been able to run for 4 or more weeks. Cycling will maintain your aerobic abilities, but it just can’t fully compensate for the demands of running.
The answer depends on your running experience, but for a “typical” runner I would recommend replacing your run workouts in the plan with the following schedule once you are to run again. This is a conservative return to running:
Week 1:
3 times a week 30 minutes Zone 1-2
Week 2:
2 times a week 30 minutes Zone 1-3, 1 time a week 45 minutes
Week 3:
2 times a week 40 minutes Zone 1-5, 1 time a week 60 minutes
Week 4:
2 times a week 45 minutes Zone 1-5, 1 time a week 90 minutes
Week 5:
Follow your plan
For the Zone 3-5 work, you’ll have to self-monitor your intensity balance and ensure you are performing 80/20 running. This is just tracking that 48 minutes out of every hour of running is Zone 1-2, and the balance Zone 3-5.
David