Zadam said:
Perhaps its because I don't follow Baseball at all, but I have no idea what you mean!
"Swinging for the fences" means, basically, in D&D terms, "All Power Attack, All the Time!"
You are trying, with every swing, to hit a home run - massive damage.
Relatively speaking, batters have a pretty easy time knocking straight-down-the-middle-of-the-plate fastballs out of the park. Thus, if someone is swinging for the fences, you don't pitch fast and easy. If someone is full power attacking all the time, you don't send low-AC melee mooks at him (unless you want him to slaughter them easily).
Instead, you throw in a slider, or a change-up - pitches that may *look*, initially, like fastballs down the middle, but which end up either going low and outside or being slow - making the batter's "Power Attack" miss. To continue the D&D analogy, send ranged attackers, flying creatures, high-AC-low-mobility types, etc.