Definitely lift in season, or you will lose muscle mass. You don't really need weight progression or big volume, just do a little bit. Twice a week for half an hour already will get you most of the way. When it comes to gaining you need more effort but maintaining only takes a tiny bit of effort.
You might still lose a tiny bit but most will be maintained, but if you don't lift at all you can easily lose like 20 % of your strength.
You don't need to max out or kill yourself but at least do something.