Glossary
Term |
Definition |
How To Impress Your Friends |
Barrel Rate |
A well-struck ball where
the combination of exit velocity and launch angle generally leads to a
minimum .500 batting average and 1.500 slugging percentage. |
"Barrel rate is the most predictive power stat. Want to see
who is capable of consistently hitting a bunch of homers? Look for elite
barrel rates." |
Command |
A pitcher’s ability to
place the ball where he wants to. |
“Command is more important than control for a pitcher, as
getting pitches to do what you want more often generate both swinging and
called strikes.” |
Control |
A pitcher’s ability to
throw strikes. |
“Man, that pitcher has a high zone rate, but it doesn’t seem
like he’s able to execute his game plan consistently due to poor command.” |
Exit Velocity |
How hard the ball comes off
the bat on a batted ball. |
"Aaron Judge led baseball last year with nearly a 96 MPH
average exit velocity!" |
Expected Batting Average (xBA) |
The odds that a batted ball
becomes a hit, based on launch angle and exit velocity. Sprint speed is also
factored in on weak groundballs. |
"While Tommy Edman doesn't hit the ball very hard, he has a
great 14 degree launch angle to hit line drives and
have a great xBA." |
Expected Slugging Percentage (xSLG) |
Calculated in a similar way
as xBA, but also factors in the likelihood of a
type of hit (single, double, etc.) |
"Miguel Sano strikes out way too much, but his xSLG of .544 shows that he hits the ball extremely hard
when he does make contact." |
Expected Weighted On-Base Average (xwOBA) |
wOBA adjusted for launch angle and exit
velocity. |
"Alex Bregman's 90th percentile wOBA
last year was great, but how much do we believe given all the trash-can
banging?" |
Hard-Hit Rate (HH%) |
The percentage of batted
balls that leave the bat with at least 95 MPH exit velocity. |
“Yes, hard-hit rate is important, but it has been proven that
barrel rate is a more predictive stat.” |
Isolated Power (ISO) |
Calculated as slugging
percentage minus batting average. League average is ~ .140. |
"Another reason Mike Trout is good at baseball? His
.353 ISO is absurd. To put this in perspective, Babe Ruth has a career .348
ISO!" |
K% |
How often a pitcher strikes
a hitter out, calculated as strikeouts divided by total batters faced. |
“This metric is better than K/9 because a pitcher's K/9 can be
artificially inflated due to the number of hitters he faces in an inning.” |
Launch Angle |
The angle at which a ball
is hit. 0 degrees represents a flat swing. Anything above 0 degrees
represents a flyball or line drive, and anything below 0 degrees represents a
groundball. |
"Ian Desmond had a negative launch angle in 2019 - he can't
be expected to hit 20 homers in 2020, no matter how much playing time he
gets." |
Roto League |
Short for rotisserie. In
these types of leagues, you pick certain categories, and the best mark in
each category is awarded the top score, with the goal being to accumulate the
highest score across all the categories. The most popular roto league categories
are considered average, HR, R, RBI, SB (five hitting); W, ERA, WHIP, K, SV
(five pitching), or "5x5." Other common categories include OBP,
Holds, and Quality Starts. |
"I'm playing in a couple roto leagues this year. I'm pretty
pumped for my 6x6 league that includes holds and on-base percentage, rather
than the standard 5x5 categories." |
Spin Efficiency |
How much the ball moves vertically
when pitched. |
Spin efficiency gives the ball life and ride, which typically
throws hitters off. |
Spin Rate |
How much the ball rotates when
pitched, changing the ball’s trajectory. |
You don’t always want a high spin rate. For changeups, a lower
spin rate actually creates more movement. |
Tunneling |
Pitchers making different
pitches look identical for as long as possible. |
Many pitchers try to tunnel their pitches, where at the exact
same point a slider darts away from the hitter as a fastball would go in on
the hands. |
Weighted On-Base Average (wOBA) |
Weighs the different types
of ways to reach base (walks, hit by pitches, types of hits) to create one
metric. The coefficients to weigh each type of way to get on base changes
each year. The league average is typically .315-.320. |
"The league average wOBA is
typically around .320." |
Weighted Runs Created (wRC) |
Represents the different
ways in which a hitter provides value compared to the league average, based
on wOBA. |
"Anthony Rendon's wRC of
133 was a career-high last year. No wonder he got that mega-deal with the
Angels!" |
Weighted Runs Created Plus (wRC+) |
Adjusted for park and
league effects in which the league average is 100 |
"Rendon's 133 wRC translates to a
154 wRC+, meaning that he was 54% better than
league average after adjusting for league and park effects." |
Zone Rate |
How often a hitter sees
pitches in the strike zone, or how often a pitcher throws pitches in the
strike zone. |
“One thing that helped Lucas Giolito
transform into an ace was his league-high 47% zone rate. Teammate Reynaldo
Lopez was second best – something’s in the Chicago water!” |