Day games at AT&T tend to be a little higher scoring due to the better weather conditions. This O/U line would be an automatic UNDER if it were a night game.
If both pitchers are ON (and both of them have had times when they were NOT), then it may stay UNDER, but I think it goes OVER, like a 4-3 or 5-2 game. I'm a SF homer, but I don't think LA gets shutout 3 games in a row, even with MadBum on the bump.