I was reading the PBC Blog last night and noticed a link to this Wall-Street Journal article. The article suggested that groundballs could be the new strikeouts in baseball, and talked briefly about how the Rockies have gone with groundball pitchers like Ubaldo Jimenez, while the A’s have reloaded their rotation with ground ball specialists.
That got me thinking about the importance of ground balls. A strikeout takes at the least three pitches to record an out. A ground ball only takes one pitch. A strikeout pitcher can also be impacted by walks (Oliver Perez) or home runs (Johnny Cueto), which totally negate the benefit of strikeouts.
I’m a big fan of three ratios: K/9, K/BB, and HR/9. I believe that strikeouts, walks, and home runs are the only stats that a pitcher has complete control over. I consider ground ball ratios to be in that group, since a pitcher often has a tendency to influence where the ball is going to go.
I decided to do a little research myself on the impact of ground balls. I took all of the “qualified starters” at FanGraphs from the 2002-2008 seasons (I assume “qualified” means 162 IP or more per season). The total number of pitchers amounted to 610 (that’s not 610 different pitchers, just 610 different events as some pitchers are counted for multiple seasons).
Ground Ball Impact
The first thing I did was sort the pool of pitchers by their ground ball rate. I divided the pool in to two groups: Over 43% and Under 43%.
There were 352 pitchers in the “Over” category, and 258 pitchers in the “Under” category.
The 352 pitchers in the “Over” category combined for a 3.99 ERA.
The 258 pitchers in the “Under” category combined for a 4.18 ERA.
It should also be noted that of the 23, 20-game winners in this time span, 14 were in the “over” category. Of the 181, 15-game winners in this time span, 109 were in the “over” category.
So in conclusion, the ground ball pitchers combined for an ERA that was 0.19 points better than the non-ground ball pitchers. There were also more 20-game winners in the “ground ball” group (14 to 9) and more 15-game winners (109 to 72).
This doesn’t necessarily guarantee success. For example, some of the guys in the “ground ball” group were guys like Mike Maroth, and two pitchers well known to Pirates fans: Kip Wells and Josh Fogg.
Factoring in K/9
I decided to take the ground ball pitchers, and divide them up by their K/9 ratios. I’m not necessarily looking for guys like Tim Lincecum, who strike out a batter an inning. I went conservative, dividing the group between guys with a K/9 above 6.0, and guys with a K/9 below 6.0.
This time I found some big differences.
The strikeout pitchers combined for a 3.71 ERA and a 1.27 WHIP.
The non-strikeout pitchers combined for a 4.29 ERA and a 1.37 WHIP.
The strikeout pitchers made up 12 of the 14, 20-game winners and 67 of the 109, 15-game winners.
So by factoring in K/9 ratios, we put a big divide in this group. I’m sure anyone would take a 3.71 ERA and a 1.27 WHIP. However, I’m not done. We still have our buddy Kip Wells making four appearances. This is mostly due to the fact that Wells has a high ground ball ratio, and decent strikeout numbers. The problem with Wells is his lack of control.
For example, in 2005 Wells had a 44.7% ground ball rate, and a 6.53 K/9 ratio. However, Wells had horrible control, leading to a 1.33 K/BB ratio, which is part of the reason why he ended up with a 5.09 ERA that year.
Removing Kip Wells
The final step I took was factoring in K/BB ratios (I am not factoring in HR/9 ratios, since those are usually lower for ground ball pitchers). I divided the “ground ball/strikeout” pitchers in to two groups: guys with a 2.0 K/BB ratio or greater, and guys with a K/BB ratio of less than 2.0.
The final step removed 36 events, leaving us with 142 pitchers in the seven year span. This includes four Kip Wells events.
The pitchers with the good K/BB ratios combined for a 3.58 ERA and a 1.23 WHIP.
The pitchers with poor K/BB ratios combined for a 4.24 ERA an a 1.44 WHIP.
The good K/BB ratio pitchers accounted for all 12 of the 20-game win seasons, and 61 of the 67, 15-game win seasons.
The Best of the Best
Out of 610 pitching seasons surveyed, I ended up with 142 seasons by factoring in the following qualifications:
Ground Ball % of 43% or greater
K/9 ratio of 6.0 or greater
K/BB ratio of 2.0 or greater
The most common names?
-Brandon Webb, John Lackey, and Roy Oswalt with five seasons.
-Andy Pettitte, CC Sabathia, Dan Haren, Jeremy Bonderman, Matt Clement, and Roger Clemens with four seasons.
-AJ Burnett, Ben Sheets, Brad Penny, Brett Myers, Chris Carpenter, Felix Hernandez, John Smoltz, Kelvim Escobar, Kevin Millwood, Mike Mussina, Roy Halladay, and Randy Johnson with three seasons.
-51 pitchers with 2 or 1 seasons
The Pirates had two players in this group of pitchers: Ian Snell in 2007 and Paul Maholm in 2008.
Those are all great pitchers, and it’s really no surprise. We’re looking at pitchers who:
1. Keep the ball on the ground (fewer homers, extra base hits, and more easy outs)
2. Post decent strikeout numbers
3. Don’t allow many walks
The big question is: how much does the ground ball factor impact the results?
Removing GB Ratios
Going back to the original group of 610 pitchers, there were 271 pitchers with at least a 6.0 K/9 and a 2.0 K/BB.
The pitchers with a GB ratio of 43% or better had a 3.58 ERA and a 1.23 WHIP.
The pitchers with a GB ratio of less than 43% had a 3.85 ERA and a 1.23 WHIP.
So while the ground ball pitchers have better numbers, it’s not that big of a difference, and it’s not like you’d turn away a pitcher with a 3.85 ERA.
Looking at the remaining pitchers, with the low K/9 and K/BB ratios:
The pitchers with a GB ratio of 43% or better had a 4.28 ERA and a 1.38 WHIP.
The pitchers with a GB ratio of less than 43% had a 4.52 ERA and a 1.39 WHIP.
Once again, the pitchers with a better GB ratio had the better numbers.
I agree with the Wall Street Journal article that not only are ground balls valuable, but they’re possibly undervalued, and the next big thing. However, I don’t think they’re going to replace strikeout pitchers.
As seen above, the pitchers with the ground ball ratios had the better numbers every step of the way. However, when you factor in K/9 and K/BB ratios, you go from having a solid #4-5 starter with a 4.28 ERA, to having a top of the rotation guy with a 3.58 ERA.
Focusing on ground balls is a great way to find some cheap pitchers to fill out the rotation, but if you want an ace, you’re going to need strikeouts and good control to go with the ground ball tendencies.