No, you probably don't need permission from the players to use their image but you will need permission from the copyright owners of the images you are using.
The right of publicity. The right of publicity gives individuals the ability to stop the unauthorized commercial use of their likeness or personna. The right of publicity typically does not prevent editorial or informational uses, only commercial uses. For example Michael Jordan could prevent the unauthorized use of his likeness in a supermarket advertisement, but James Brown could not halt the sale of James Brown images by Corbis, a stock photo company that provided images for editorial uses. As long as you avoid creating the impression that the baseball players endorse your book -- that is, you don't use the player's likeness in the ads or on the cover of the book -- you should not have any right of publicity issues.
Copyright permissions. What's the source for your photographs? If you've been grabbing screenshots from the Internet, you may run into a problem if the copyright owner sees your book. That's because most baseball imagery from the past fifty years is still protected by copyright. If you've been operating with pictures from fee-based stock photos services such as Getty, AP Images, or MLB, you should be fine.
P.S. Don't forget trademarks. If prudence is your thing, avoid MLB references in ads or on the cover of your book.
