I think you should get a prop bat.
I'll tell you the method I used, but I must reiterate that the person swinging the bat is not just fully trained in stage fighting, but is very athletic, strong, and in control of himself, physically. I don't recommend this method for just anybody.
We broke it down into 3 shots. The first shot was BadGuy picking up the bat, and beginning a swing. He stopped the swing very well short of even coming close to making contact.
The second shot just showed BadGuy swinging, from a different angle, coming closer to striking his contact. This angle was from the front, and zoomed-in, so that the audience could not tell that the bat actually stopped short of making contact, by about a foot.
In the third shot, we made contact, but the bat only started about 6-inches away from the subject. In such a short distance, there's not really any worry of injury, especially with the person swinging only going 75%. The "forcefullness" of the hit was sold by the actor being hit.
You can see the first two shots, near the end of the
trailer.