Hitters are swinging earlier, and it's working

MLB swing rates are increasing against starters' early offerings

March 21st, 2018

For much of the early part of this century, the prevailing offensive strategy was simple: Take pitches in hopes of wearing out the opposing starter and get to the middle relievers as quickly as possible. The Red Sox and Yankees did this famously, and many other teams followed suit.

But teams' relief corps are no longer the soft-throwing underbellies of the staffs; they're coming out firing. The average Major League reliever had a harder fastball in 2017 (93.7 mph) than a decade ago (92.1 mph), and more of them are hitting at least 98 mph on the radar gun (110 relievers in '17, 73 in '08). Relievers are also striking out more hitters (23.3 percent strikeout rate in '17, 19.2 percent in '08) than they used to.

Hitters will always adjust to pitchers, and vice versa. So faced with a cavalcade of flamethrowers and strikeout artists, it appears they may be changing their approach. Namely, they're beginning to attack pitchers before pitchers can attack them. Fans are likely aware of the home run surge taking place across all levels of professional baseball. But there's another shift happening. Yes, hitters are swinging for the fences, but they're also swinging earlier -- particularly against starting pitchers.

Hitters have begun swinging more on the first two pitches of at-bats (0-0, 1-0 and 0-1 counts) against starters in recent years. Compounded over entire seasons, those percentage bumps mean hitters have taken several thousand more cuts at early pitches over recent years. The trend accelerated after the 2015 All-Star Game -- the same time MLB's home run rate began climbing -- and hitters have inflicted serious damage since they've become more aggressive.

Weighted on-base average (wOBA) is a statistic similar to OBP, except it gives hitters increasingly more credit for how they reach base (more weight for doubles, triples and home runs). By this measure, big league hitters are finding more success when putting these early pitches into play, improving from the power level of Didi Gregorius (.191 ISO in 2017) to (.242) in the span of four years. That includes more home runs:

Home runs per ball in play on the first two pitches vs. starters in 2014-17

2014: 3.5 percent

2015: 4.0 percent

2016: 4.9 percent

2017: 5.1 percent

Even that 1.6 percent increase over four seasons has translated to nearly 400 more homers early in the count. It may be getting harder for a starting pitcher to sneak in a first-pitch strike now that hitters are more willing to swing, and swing big.

Who's thriving on this strategy the most? Earlier this winter, MLB.com highlighted how and , the American League's top two hitters by average last season, feasted on the first pitch of at-bats. When looking at a cross-section of baseball's most aggressive and most successful hitters when putting starters' early pitches in play, some of 2017's best hitters stand out.

The Astros employed this aggressive approach selectively but effectively in last year's postseason. Facing Chris Sale in Game 1 of the American League Division Series, Altuve attacked a first-pitch fastball for his second homer off the strikeout king. clubbed two of his six postseason homers off early pitches from Rich Hill and . And Yuli Gurriel's game-tying three-run dinger off 's first-pitch slider in Game 5 may have been the turning point of the World Series.

Like the homer surge, it's worth monitoring whether hitters will continue being more aggressive this season. The strategy appears sound, as hitters' wOBA in deep counts (i.e., three-ball or two-strike counts) has languished below .300 for the past decade. Starters want to get ahead of hitters by throwing early strikes, and it seems hitters are willing to swing more at those offerings now. The days of waiting for the bullpen could be coming to an end; it's time to attack early and often.