This image of a bat, helmet and baseball is available as a scalable vector graphic so it will work well for print media!
Here's a cute cartoon of the umpire getting ready to catch the ball if the batter misses hitting it.
This one's vintage image that might have been from an old poster or old advertisement for the local team.
The next 4 are vectors created from vintage images. This one of a pitcher and the next one are from "The Art of Caricaturing" by Mitchell Smith, created in 1941.
This one of a pitcher and the next one are from "Caricature, the Wit & Humor of a Nation in Picture, Song & Story" in 1911.
Again, this black and white image of a ball player running for home plate is a vectorized vintage image.
This baseball cap is available as both a large transparent png and a scalable vector graphic so it would work well for print at any size.