I think everyone has a hard time hitting a knuckleball, it can be very challenging in this years game or any baseball video game. I have two videos one of me facing both of the best knucklers in the game and a way to practice against them. No I am not the best player but I have a fun time playing this game. I hope this helps!
I love Knuckleball pitchers.
I noticed that they have the CotW featuring a KB pitcher right now. Good place to practice a little.
This is also a good option! I did mention that in my video. And there is an easy way to practice against niekro and tiant on legend