How do you even out muscle tone/size disparities from playing racket sports?

I work out at least 5 times per week, lift for about an hour and a half then cardio is playing 4–5 games of racquetball. After just a month or two of doing this im noticing (predictably) that my dominant arm is feeling much bigger and its starting to become obvious in the wieghtlifting now, as I am able to complete sets more easily with my dominant arm (it wasnt like that when I was exclusively lifting). Any tips on staying away from turning into a lobster?