I do a baseball unit w/ my 4th graders, and will start it in a few weeks. Here are some activities I do.
Student Baseball Cards:
Each student creates a baseball card about himself/herself. The stats are just facts about themselves.
Students draw from a hat a professional player's name. Then we spendsome time doing research online and using books. Students then create a "baseball card" for their player. You can even have the students do a "trading day" with their cards.
Baseball spreadsheet and graph:
Students choose a baseball team to track for ten games. They keep up with wins/losses for the 10 games on a spread sheet in excel. Then we use that data to create a graph.
by Barbara Park (novel, my favorite & students' favorite)
Baseball Saved Us
not sure who the author is, but it is based on a "camp" during Vietnam War (or maybe WWII???) and how they played baseball to pass time
not sure who the author is
There are many others, but I can't think of them right now.
Hope you hit a "grand slam" with your baseball unit!