Well, the good news is you're going to a baseball rich country soon. If there's really no infrastructure to accommodate a baseball player then I would suggest simply focusing on making yourself the best athlete you can. Get yourself is as good of shape as possible (don't overdo it with weight training, as it could harm your natural development; just light weight training, moderate to heavy cardio).
You could also try getting something like this so you can practice taking ground balls, and work on your reflexes and arm accuracy. You could also get a batting tee so you can start to get a feel for your swing. I wouldn't go too crazy with batting practice since you probably won't have a field to use, just put the tee in front of a fence and work on being able to square up the baseball consistently. If you can't get equipment then just work on the athletic training.
I would think at some point the infantry would become very adept at hearing the drones or having lookouts for them, or some sort of rollaway mesh material to pull over the trenches.....pretty sad when this thing would save your life... Pitching rebounder
Go to a cage. A cheap (pitchback)[https://www.amazon.com/SKLZ-PitchBack-Baseball-Throwing-Fielding/dp/B003D6FDBY/ref=cm_cr_arp_d_product_top?ie=UTF8] in your yard can help with throwing/catching. Have a buddy hit you some pop ups in a field and run around trying to catch them.
Baseball pitch back. https://smile.amazon.com/SKLZ-PitchBack-Baseball-Throwing-Fielding/dp/B003D6FDBY
I set up one of those nets that baseball players practice their throwing into. Like this
https://www.amazon.com/dp/B003D6FDBY/ref=cm_sw_r_cp_apa_i_II.tFbGDCAC0H
And I just crash my drone into that instead of actually land.