Which day is best to add workouts for injured runners

This morning I was on a webcam call with a runner who had healed a fracture and started running again. He has been running every Monday, Wednesday and Friday, with cross-training in between.     Now he is ready to add a fourth running workout to his weekly training schedule.    The question is:    “What day of the week is best to add an additional run, because I want to make sure I don’t overload the healing tissue and re-injure it.”   Today on the Doc On The Run podcast, we're talking about which weekday is best to add workouts for injured runners.