This is the beginning of the classic R.E.M. sound. The albums before Lifes Rich Pageant feature a little noodling and experimentation with what R.E.M. could be, but this album is where their sound got laid down in concrete. When you think of R.E.M.'s big hits, most of them were written in the style laid out on Lifes Rich Pageant.
Tracks like "Fall on Me" "What if We Give it Away" and "I Am Superman" could just as easily be on any of the 5 albums that come after Lifes Rich Pageant than anywhere else. On this album R.E.M. really found their stance and just started swinging for the fences (the baseball reference is a nod to Peter Buck and the excellent Baseball Project, which is a collaboration with Young Fresh Fellows' Scott McCaughey).