It is no secret that the best outcome for a pitcher is a strikeout. There are no ifs, ands, or buts about that statement of fact. That's the way it has always been and that's the way it will always be. Except for the rare missed third strike, a strikeout always produces an out and no chance for runners to advance bases (other than a stolen base).

Among batted ball types, we know that infield flies are the least harmful, followed by groundballs, outfield flies, and line drives. In fact, thanks to researchers like Dave Studeman of The Hardball Times, we can even place a value on the run impact of each event. For example, according to Dave's Batted Balls Redux article in The Hardball Times Baseball Annual 2007, strikeouts had a run impact of -0.113, infield flies -0.088, groundballs 0.045, outfield flies 0.192, and line drives 0.391 per incident in 2006.

Although groundballs generate more hits and errors than flyballs, their run impact is lower because the hits are usually limited to singles and an occasional double down the first or third base line, whereas balls in the air that turn into hits more often become doubles, triples, or home runs. Not only is the run impact from a groundball lower than an outfield fly or line drive but groundball pitchers give up fewer line drives and flyballs. Conversely, pitchers who don't induce as many groundballs allow more line drives and flyballs. One of the basic truths of maintaining a low home run rate is to keep batted balls on the ground. It is also important to note that home run rates tend to fluctuate more than groundball rates because park effects and randomness play a huge role when it comes to the outcome of long flyballs, especially among pitchers.

Based on the above information, it follows that just as pitchers with high strikeout rates would generally fare better than those with low rates, pitchers with high groundball rates would normally fare better than those with low rates (all else being equal). Furthermore, it also suggests that pitchers who combine higher strikeout and groundball rates will outperform those with lower rates.

With the foregoing in mind, in January 2007, I introduced the idea of categorizing starters and relievers by strikeout and groundball rates. Due to the popularity of this series, I have decided to categorize pitchers based on the 2007 data. Like last year, I have greatly benefited from the help of David Appelman of FanGraphs in creating graphs that plot strikeout and groundball rates separately for starters and relievers (featured in part two on Tuesday).

The x-axis is strikeouts per batter faced (K/BF) and the y-axis is groundball percentage (GB%). The graph for the starting pitchers (defined as major leaguers who completed 100 or more innings and started in at least 33% of their appearances) is divided into quadrants with the mid-point equal to the average K/BF of 16.33% and the average GB% of 43.88%. By placing pitchers in quadrants, one can easily ascertain those with above-average strikeout and groundball rates (referred herein as the northeast quadrant), above-average strikeout and below-average groundball rates (southeast quadrant), above-average groundball and below-average strikeout rates (northwest quadrant), and below-average groundball and strikeout rates (southwest quadrant).

Looking at the outliers in the graph is one of the most interesting aspects of this study. Starting with the northeast quadrant and going clockwise, Derek Lowe, Brandon Webb, Felix Hernandez, A.J. Burnett, Erik Bedard, Jake Peavy, Scott Kazmir, Johan Santana, Chris Young, Chuck James, Jason Hirsh, Matthew Chico, Steve Trachsel, Aaron Cook, and Fausto Carmona all stand out for their extreme (good or bad) strikeout and/or groundball rates. Is there anybody who wouldn't take the outliers in the northeast quadrant over the outliers in the southwest quadrant? Lowe (3.88), Webb (3.01), Hernandez (3.92), Burnett (3.75), Bedard (3.16), and Peavy (2.54) all had much lower ERAs than Hirsh (4.81), Chico (4.63), and Trachsel (4.90).

Let's take a closer look at the results. Pitchers in the northeast, southeast, and southwest quadrants are sorted by K/BF rates. Pitchers in the northwest quadrant are listed in the order of GB rates.

NORTHEAST QUADRANT (ABOVE-AVG K AND GB RATES)

Pitcher               K/BF      GB%
Erik Bedard          30.15%    47.87%
Jake Peavy           26.73%    44.00%
A.J. Burnett         25.47%    54.82%
Tim Lincecum         24.27%    47.04%
Josh Beckett         23.60%    47.31%
John Smoltz          23.09%    44.69%
C.C. Sabathia        21.44%    45.00%
Dan Haren            20.53%    44.44%
Dustin McGowan       20.43%    53.04%
Felix Hernandez      20.42%    60.83%
Ian Snell            20.07%    45.93%
Brandon Webb         19.90%    61.76%
Kelvim Escobar       19.70%    44.00%
John Lackey          19.27%    44.69%
Jeremy Bonderman     19.26%    47.91%
Carlos Zambrano      19.14%    46.85%
Daniel Cabrera       18.00%    49.51%
Jeff Francis         17.90%    44.39%
Derek Lowe           17.69%    64.97%
Boof Bonser          17.62%    45.05%
Chad Gaudin          17.38%    50.97%
Mark Hendrickson     17.29%    44.13%
Gil Meche            17.22%    46.81%
Edwin Jackson        16.95%    45.06%
Roy Oswalt           16.92%    52.97%
Doug Davis           16.71%    47.02%

There are a number of outstanding arms in the group above. The best of the lot are those with strikeout rates north of 20 and/or groundball rates in the low-50s and above (both of which would be about 20% over the averages). Interestingly, Bedard, Burnett, Josh Beckett, John Smoltz, C.C. Sabathia, Dan Haren, Hernandez, Webb, Kelvim Escobar, Jeremy Bonderman, Carlos Zambrano, Roy Oswalt, and Doug Davis are all northeast quadrant returnees from last season.

Lowe graduated from the northwest quadrant (13.47% K/BF and 67.04% GB in 2006) to the northeast quadrant (17.69% and 64.97%) by improving his strikeout rate 4.22 percentage points or more than 30% while excelling at inducing grounders. The righthanded sinkerballer had the best groundball and line drive (15.8%) rates in the NL last season. Amazingly, he also had the highest home run rate as a percentage of flyballs (17.1%). According to THT, "research has shown that about 11% to 12% of outfield flies are hit for home runs. For pitchers, significant variations from 11% are probably the result of 'luck'." Here's betting that Lowe's GB will remain fairly steady while his HR/FB rate regresses toward the league mean.

The biggest surprises in the northeast quadrant for me were Mark Hendrickson and Edwin Jackson. However, both had K and GB rates that were close to the league average. As such, I wouldn't classify either as a special pitcher. If anything, I would think of Jackson more along the lines of Daniel Cabrera, another power arm, than not. Both are blessed – or cursed as it may be – with that "p" word, as in potential.

SOUTHEAST QUADRANT (ABOVE-AVG K AND BELOW-AVG GB RATES)

Pitcher               K/BF      GB%
Scott Kazmir         26.94%    43.15%
Johan Santana        26.77%    38.02%
Javier Vazquez       24.15%    39.77%
Cole Hamels          23.82%    41.87%
Chris Young          23.69%    29.15%
Daisuke Matsuzaka    23.00%    38.39%
Aaron Harang         23.00%    40.27%
Oliver Perez         22.75%    32.79%
Chad Billingsley     22.63%    41.04%
Rich Hill            22.54%    36.01%
John Maine           22.22%    36.96%
Yovani Gallardo      21.67%    38.17%
Justin Verlander     21.13%    41.12%
James Shields        21.05%    43.38%
Orlando Hernandez    21.05%    37.75%
Ted Lilly            20.54%    33.67%
Randy Wolf           20.52%    40.78%
Wandy Rodriguez      20.20%    41.44%
Chris Capuano        19.73%    42.95%
Matt Cain            19.59%    39.44%
Byung-Hyun Kim       19.04%    40.17%
Ervin Santana        18.67%    35.64%
Shaun Marcum         18.48%    40.17%
Jason Bergmann       17.92%    33.43%
Ben Sheets           17.91%    36.53%
Brett Tomko          17.86%    41.01%
Claudio Vargas       17.69%    33.79%
John Danks           17.52%    34.76%
Andrew Sonnanstine   17.51%    38.94%
Brian Burres         17.17%    37.73%
Jeremy Guthrie       17.01%    42.49%
Bronson Arroyo       16.94%    35.28%
Scott Baker          16.83%    34.64%
Chuck James          16.79%    30.99%
Jered Weaver         16.55%    35.65%
David Bush           16.54%    43.36%

There are at least a dozen outstanding pitchers in this group, most notably those listed in the top half (or with K rates over 20%). Kazmir just missed the northeast quadrant although he had K and GB rates that were almost identical to Peavy, who just so happened to win the Triple Crown of pitching by leading the NL in ERA, wins, and strikeouts.

Young had the ninth-highest K/BF rate of all starting pitchers and was the only one with a GB% below 30. Despite being an extreme flyball pitcher, Young has benefited by pitching his home games at Petco Park, which tied with Busch Stadium for the second-lowest HR rate in the majors in 2007 (behind only RFK Stadium).

NORTHWEST QUADRANT (ABOVE-AVG GB AND BELOW-AVG K RATES)

Pitcher               GB%       K/BF
Fausto Carmona       64.31%    15.59%
Tim Hudson           61.96%    14.27%
Sergio Mitre         59.73%    12.08%
Chien-Ming Wang      58.45%    12.64%
Aaron Cook           57.89%     8.74%
Kameron Loe          56.33%    12.68%
Lenny DiNardo        56.28%    10.63%
Julian Tavarez       53.78%    12.75%
Jake Westbrook       53.54%    14.35%
Paul Maholm          53.25%    13.73%
Roy Halladay         53.10%    14.99%
Greg Maddux          51.48%    12.53%
Zach Duke            50.62%     8.51%
Jason Marquis        49.52%    12.88%
Brad Thompson        49.46%     9.14%
Justin Germano       49.19%    13.78%
Joe Kennedy          48.93%    10.18%
Brad Penny           48.72%    15.61%
Matt Morris          48.48%    11.54%
Kip Wells            48.21%    16.27%
Sean Marshall        48.18%    15.02%
Adam Wainwright      48.15%    15.42%
Jesse Litsch         48.14%    10.46%
Matt Albers          47.99%    13.98%
Andy Pettitte        47.69%    15.39%
Carlos Silva         47.54%    10.50%
Chris Sampson        47.31%     9.77%
Kyle Kendrick        47.06%     9.82%
Joe Blanton          46.95%    14.74%
Dontrelle Willis     46.44%    15.50%
Kevin Millwood       46.42%    15.61%
Vicente Padilla      45.69%    12.84%
Joe Saunders         45.38%    14.59%
Jeff Suppan          45.38%    12.40%
Odalis Perez         45.36%    10.22%
Noah Lowry           44.92%    12.54%
Jose Contreras       44.89%    13.17%
Nate Robertson       44.63%    15.24%
Edgar Gonzalez       44.54%    14.19%
Miguel Batista       44.07%    15.47%
Chad Durbin          43.95%    11.76%

This is an interesting group of pitchers, ranging from the highly successful (Carmona, Tim Hudson, Chien-Ming Wang, Roy Halladay, and Brad Penny) to those fighting for a spot in a starting rotation or even the majors (Kameron Loe, Julian Tavarez, Jason Marquis, Brad Thompson, Justin Germano, Kip Wells, Sean Marshall, Matt Albers, Chris Sampson, Odalis Perez, Edgar Gonzalez, and Chad Durbin). There are also several hurlers who are still serviceable but have seen better days, such as Greg Maddux, Matt Morris, Andy Pettitte, and Kevin Millwood, as well as enigmas like Dontrelle Willis.

As a whole, they rank behind those in the NE quadrant and ahead of those in the SW quadrant. Opposite of the pitchers in the SE quadrant, the NW inhabitants succeed by inducing grounders and keeping the ball in the park, whereas their counterparts thrive on strikeouts.

SOUTHWEST QUADRANT (BELOW-AVG K AND GB RATES)

Pitcher               K/BF      GB%
Micah B Owings       16.28%    37.45%
Matt Belisle         16.21%    41.75%
Josh Towers          16.20%    43.85%
Scott Olsen          16.10%    37.65%
Buddy Carlyle        16.02%    32.35%
Curt Schilling       15.96%    37.27%
Kyle Davies          15.76%    38.83%
Anthony Reyes        15.61%    35.17%
Jason Hirsh          15.53%    30.17%
Tom Gorzelanny       15.45%    42.09%
Barry Zito           15.41%    39.12%
Jamie Moyer          15.34%    39.41%
Kyle Lohse           14.72%    36.89%
Jorge de la Rosa     13.92%    40.63%
Mike Mussina         13.87%    41.91%
Mark Buehrle         13.77%    43.23%
Tim Wakefield        13.75%    38.90%
Jarrod Washburn      13.59%    36.54%
Adam Eaton           13.22%    39.29%
Brandon McCarthy     12.85%    35.76%
Josh Fogg            12.62%    40.04%
Matthew Chico        12.58%    33.39%
Jeff Weaver          12.18%    35.80%
Woody Williams       12.12%    39.16%
David Wells          11.82%    43.53%
Braden Looper        11.66%    42.16%
Brian Bannister      11.27%    40.83%
Jon Garland          11.10%    39.44%
Paul Byrd            10.54%    38.26%
Tom Glavine          10.41%    41.75%
Livan Hernandez       9.86%    38.45%
Mike Maroth           9.29%    42.53%
Mike Bacsik           8.65%    40.84%
Steve Trachsel        7.98%    41.16%

Repeating what I said last year, "this is the quadrant that you want to avoid. It is inhabited by some of the worst starters in the game. If you fail to miss bats and don't keep the ball on the ground when it is put into play, you are going to run into trouble." There are two ways to survive (or perhaps semi-survive) in this quadrant: (1) being close to league average in both K and GB rates and (2) throwing strikes and maintaining a low walk rate. Matt Belisle, Josh Towers, and Tom Gorzelanny fit the first bill, while Belisle, Towers, Curt Schilling, Kyle Lohse, Mike Mussina, Mark Buehrle, Jeff Weaver, and David Wells would qualify under the second scenario. However, all of these types of pitchers live on the edge with very little margin for error.

When it comes to evaluating pitchers, I would rather know their strikeout and groundball rates than their ERA. Throw in walk rates and you have almost everything you need to know about a pitcher. Focusing on these components gives one a much more comprehensive understanding of a pitcher's upside and downside than looking at a single metric such as ERA.

Tomorrow: Categorizing Relievers by Strikeout and Groundball Rates.