How plate discipline metrics can differentiate flukes from true fantasy value
Follow theScore's fantasy feed on Twitter (@theScoreFantasy) for the latest news, features and more.
Every year, under-the-radar players get off to scorching hot starts in baseball -- probably more so than in any other sport. Sometimes it can be difficult to buy into the hot start, especially if it's from a virtually unknown hitter. However, there are distinct ways to tell whether a player is just lucking his way into success, or he is actually on the verge of a breakout season.
A hot start can tempt fantasy owners into selling high on players, but it's important to dig deeper into the numbers before pulling the trigger. So much goes into a high batting average or a high amount of home runs.
Plate discipline stats can be a great way to tell whether a hitter has actually changed his approach, or whether he is just having more batted ball luck. Here are two key plate discipline stats you need to remember:
O-Swing% = Percentage of pitches swung at outside the strike zone
Z-Swing% = Percentage of pitches swung at inside the strike zone
| Stat | Good or Bad? |
|---|---|
| High O-Swing% | Bad |
| Low O-Swing% | Good |
| High Z-Swing% | Good |
| Low Z-Swing% | Bad |
The most ideal scenario is a hitter with a high Z-Swing% but a low O-Swing%. It's no surprise some of the best hitters in baseball, such as Atlanta Braves 1B Freddie Freeman and Los Angeles Dodgers SS Corey Seager, had some of the biggest differences between their Z-Swing% and O-Swing%. If a player has a large gap between the two, then trust his performance can be sustainable.
If a player begins the season with a lower O-Swing% than in year's past, it indicates a sign of maturity at the plate. Laying off pitches outside the strike zone is what young hitters struggle with most.
If a player's Z-Swing% is drastically down, they're likely being too patient. It shows they're working the count and probably drawing more walks, but it means they're not swinging at hittable pitches, which could lead to a down offensive season.
Take Minnesota Twins 1B Joe Mauer, for example. He had the fifth-best line drive percentage in baseball, the fifth-highest opposite-field percentage, set a career-high in walk rate and had his lowest strikeout rate since 2012. Despite all these positives, he hit just .261. Largely because he swung at only 50.8 percent of pitches inside the strike zone -- the lowest in the majors.
In the scenario where a player is off to a hot start but both his Z-Swing% and O-Swing% are up, it clearly shows he is being more aggressive at the plate. Pitchers will take note of this and begin to give this hitter more off-speed pitches outside of the zone.
Being an ultra-aggressive hitter only works if you have outstanding plate coverage and can be a "bad ball" hitter, such as Vladimir Guerrero. Houston Astros 2B Jose Altuve might be the best modern day example, but even he has improved his plate discipline over the years.
On the wrong end of the spectrum, Texas Rangers 2B Rougned Odor had the fifth-highest O-Swing%, but only the 38th highest Z-Swing%. His poor batter's eye was exposed late in the season, hitting just .178/.231/.356 in the final 20 games of the year. His fantasy owners should have sold high on him upon realizing his poor plate discipline stats. I wouldn't draft him at his ADP this year.
As important as it is for a hitter to have patience, fantasy owners need to have even more. Despite what these plate discipline metrics can tell you, it's still important to give a hitter at least one month -- ideally two -- before coming to a conclusion on your evaluation of him.
Advanced stats courtesy of FanGraphs.
(Photos courtesy: Action Images)