Cubs mailbag: Opening Day thoughts, in-season call-ups and more

This tweet from MLB Network’s Jon Morosi on Tuesday spoke volumes about what the World Baseball Classic represents: The night before, Japan roared back for a 6-5 semifinal victory over Mexico on a walk-off, two-run double by Munetaka Murakami. Even if you were just watching it on TV, you could feel the energy in that game. Sure, it might…