It's not something you should cram on.
Core training is one of the critical strength exercises that an athlete should work on. What is core work? Well it is not your daddy's situps.
Think work like planks, side planks, single legged squats, standing cable curls on one leg; essentially any work where you have some instability and are performing weight work.
Your weights do not need to be heavy in these workouts but you should have a full range of motion.
I would not worry but would start incorporating some core work into your weekly routines. A strong core will help prevent injuries over time.