Twenty years ago, Tony LaRussa changed the way modern baseball is played, essentially creating the role of the modern one inning closer with his innovation of having Dennis Eckersly start the ninth inning in save situations with a clean slate, usually resulting in a quick 1-2-3 inning...Game Over! Prior to that, closers rarely came in unless the previous pitcher had run into trouble, usually leaving a couple of men on base for the closer to clean up. A far more difficult task with almost no margin for error. This has lead to the modern era of cheap saves, and a manager's reluctance to use his best reliever, usually the closer, in any key situation that may arise before the ninth.
Now LaRussa is at it again. Using his entire bullpen almost very game in the NLCS vs. Milwaukee, matching up where he feels each has the advantage of opposing hitters. Sure, someone starts the game but there are no traditional starters. no one will see each pitcher a second or third time through the lineup. Good major league hitters usually begin to feast on all but the best pitchers at these times, they figure out what the pitcher is trying to do just as the pitcher is starting to tire, a lethal combination! By changing pitchers so often, in the new LaRussa method, no pitcher faces a batter twice, all the pitchers are fresh and their stuff is at it's sharpest, pitchers can pitch almost every day...it could revolutionize the game again. Teams with less talented starters (the Phillies will be very late adopters of this change) can use formerly weaker starting pitchers more frequently for shorter periods (think Kyle Kendrick, moderate stuff, but usually effective once or so through the lineup), will suddenly have effective staffs overall.
Batting averages will tumble. The game will change and adapt...for the better or worse? That depends on unforeseen consequences (will pitchers develop as well in the minors if they are never allowed starter innings to work on their craft?), or will they pitcher frequently enough that they end up with approximately the same number of innings, rendering the point moot? I don't know, but the constant changes, the moves and counter moves (yes, the hitters will adapt) are what make baseball ever fascinating