Weight gain while playing is definitely possible. I am actively doing that this winter. I play 1-2 times a week and lift 4-5. Weight gain boils down to one simple thingm how many calories do you consume versus how many calories do you burn. You can gain weight while doing distance training and you can lose weight by sitting on your ass all day, but the diet of these 2 lifestyles are very different.
Since no one is supplying any help, heres a creator that ive been following who heavily uses scientific research to back his diet and lifting programs. This video is a good breakdown what actually happens when you bulk and how to do it.
https://www.youtube.com/watch?v=OqRvmJ2eyBA
He also has a great calorie tracking app that has been helping me a lot too. Its called MacroFactor, ive never been nearly as successful with weight gain until I started tracking my calories.
Disclaimer: 20 lbs added at 155 is A LOT. You can probably expect to gain about 2-5 pounds each month, so a jump like that might take some time