By this point in the MLB season, it would be reasonable to expect that most hitters would have faced roughly the same quality opposing pitchers. But the schedule always contains quirks, and it’s impossible to have every team face every starting pitcher the same number of times. Even within divisions, the math of a five- or six-starter rotation and a three- or four-game series means that there’s some luck involved when it comes to the quality of opposition for each batter.Does it matter? Of course it does. Hitters generally do their biggest damage against pitches with poor stuff and poor locations. Against pitches with better than average Stuff+ this year, the league’s weighted on-base average (wOBA) is .243, set against a league-average .317 wOBA. Over the past three years, that’s the difference between batting like Gavin Sheets versus being worse than the worst qualified hitter over that time span (Ke’Bryan Hayes, with a .254 wOBA).It’s hard to thrive against the very best stuff in the league. Even this list of the players who have done the best against pitches with 100 Stuff+ or better (with a 175 plate appearance minimum, through Monday’s games) includes a few that have seen, among those pitches, at least poorly located high-stuff pitches. (L+ is Location+, a stat that judges location quality.)