Batted Ball Data (GB%, LD%, FB%)

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Description:

Groundball, fly-ball, and line-drive percentages represent the amount of each type of batted balls hit against a pitcher. Much like how hitters have partial control over their batted ball splits, pitchers do have a bit of control over the way the ball is put into play against them. Pitchers tend to be primarily groundball or fly-ball pitchers, but their splits aren’t as extreme as hitters. The type of batted ball also affects the likely outcome of the play as we’ll see in a bit.

Context:

League Average Rates (2005-2009)

  • GB%: 45%

  • FB%: 36%

  • LD%: 19%

Some extremes (from the last 3 years combined):

  • Jered Weaver: 47.9 FB%, 19.2 LD%, 32.9 GB%

  • Derek Lowe: 22.8 FB%, 16.9 LD%, 60.4 GB%

  • Kevin Millwood: 35.0 FB%, 21.9 LD%, 43.1 GB%

A sampling of 2009 Rays:

  • James Shields: 37.2 FB%, 20.5 LD%, 42.3 GB%

  • David Price: 39.4 FB%, 19.1 LD%, 41.5 GB%

  • Jeff Niemann: 39.5 FB%, 20.0 LD%, 40.5 GB%

  • Matt Garza: 42.5 FB%, 17.8 LD%, 39.7 GB%

  • Scott Kazmir: 45.1 FB%, 18.9 LD%, 36.1 GB%

Things to Remember:

  • Line drives are death to pitchers.
    • The expected run value for a LD is .384. Contrast that to a GB (.04) and a FB (.1).
    • The expected out value for a LD is .305. Contrast that to a GB (.8) and a FB (.79).
    • In other words, a LD produces 1.26 runs/out while GBs produce .05 R/O and FBs produce .13 R/O.
    • Fortunately, it seems that pitchers don’t have nearly as much control over line drives surrendered. This may be because pitchers who give up an inordinate amount of line drives don’t last long enough to hit the leaderboards.
  • Pitchers with higher GB rates tend to give up more hits, but they also seem to give up less extra base hits. This is relatively intuitive because groundballs are harder to field than fly-balls (resulting in a higher BABIP), but they rarely go for extra-bases (and almost never go for homeruns).

    • Links for Further Reading:

    Pitchers, Strikeouts, and Batted Balls – Baseball Analysts

    Much, Much More on Grounders – Lookout Landing

    Groundballs and the Overall Picture – FanGraphs

    Pitchers, Homeruns, and Fly Balls – FanGraphs

    The Truth About the Grounder – Hardball Times

    Groundballs and Homerun Rates – Hardball Times

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