Zack Greinke, October's secret weapon?

If I asked a majority of baseball fans who the most dangerous pitcher who could start games this postseason would be, most would say Justin Verlander, Roy Halladay, Cliff Lee or CC Sabathia. All of these pitchers have won or -- in Verlander's case, about to win -- a Cy Young award at some point during their careers. But that list of obvious greats overlooks one deserving member of this club: The Brewers’ Zack Greinke, who may actually be the most dangerous starting pitcher entering the playoffs.

In terms of SIERA (Skill-Interactive Earned Run Average), an ERA estimator, Greinke ranks first among all pitchers in baseball with a 2.40 mark. In terms of xFIP, which stabilizes a pitchers’ home run ratio, he also leads the league with a 2.46 mark, well ahead of Roy Halladay’s 2.68.

These ERA estimators like Greinke so much because of his incredible strikeout rate and solid walk rate. He has struck out 28.8 percent of the batters he has faced this season, which is the highest number since 2009, when Tim Lincecum also struck out 28.8 percent of opposing batters. Lincecum won the Cy Young award that year, but Greinke is far from contending for the award in the National League this season.

The main reason for that is that Greinke’s actual ERA is much higher than the estimators’ project. Only four pitchers have a bigger gap between their ERA and FIP, which shows that these pitchers have been at least somewhat unfortunate this season. In Greinke’s case, his home-run rate and batting average on balls in play have kept him away from the elite status that he likely deserves. His home run per fly ball rate is the highest of his career, and his BABIP is the highest it has been since 2005, his second season in the majors.

The Brewers’ ace has also had trouble stranding people on base, which is often looked at as a sign of poor luck rather than skill, especially for a pitcher with as high of a strikeout rate as Greinke. Only six pitchers have a lower left-on-base percentage than Greinke, which is not something teams will be able to count on or expect in the playoffs.

As mentioned earlier, Greinke has had great control along with his incredible penchant for striking batters out. Greinke is on the verge of becoming just the 10th starter in major league history with over 10 strikeouts per nine innings and a 4.00 K/BB. For what is least affected by outside sources -- the park he plays in, or his defense -- Greinke is on a level that not many give him credit for. Some of the other pitchers to accomplish this feat are Sandy Koufax, Randy Johnson and Pedro Martinez.

Many Cy Young voters and a majority of fans still value ERA much more than defensive-independent pitching statistics. For that reason Greinke’s season is overlooked, though much of the reason his ERA is so high is because of shaky defense at all positions aside from center field, plus a park susceptible to home runs. Greinke’s home run rate per fly ball in Miller Park is above 12 percent, yet he still managed to post a 2.89 ERA and 2.03 FIP at home.

When playoff time comes, each contending team will have its own top-notch pitchers. Although Greinke has won a Cy Young in the past, he is seemingly overlooked when talking of top-of-the-rotation arms headed to the postseason. Expect Greinke to excel in his first playoff appearance, which could propel the Brewers to the first deep playoff run they have had in over a quarter-century.

Ben Duronio writes about the Braves for the Capitol Avenue Club, part of the SweetSpot network. You can follow or tweet him at @Ben_Duronio.