Optimal Time to Rest Position Players

Major League Baseball teams play 162 games in about 180 days. With a few exceptions (such as players named Ripken or Gehrig), position players need a day off every so often to stay sharp.

For Wednesday's afternoon game, Dodgers manager Joe Torre rested four of his eight starting position players against the Diamondbacks: Rafael Furcal, Manny Ramirez, Casey Blake, and Russell Martin (all of whom, ironically, later played, as the game went 14 innings and the Dodgers needed pinch hitters). Managers often rest older players en masse in day games after the team played the night before.

Would splitting up the days off, by instead resting one starter each game, lead to more wins? Is it better to significantly reduce your chances of winning one game or slightly reduce your chances of winning four games?

I don't have a clue how someone would go about answering this question empirically.