Ace Composite Rating: Best starting pitchers of the first half

Rick Osentoski-USA TODAY Sports

In recent weeks I've been dabbling with a new statistic that I created to evaluate starting pitchers. That statistic is called Ace Composite Rating (ACR). Up to this point, I've only used ACR to evaluate the starting pitchers for the Detroit Tigers. The calculations I arrived at using ACR numerically confirmed what I was seeing out of Tiger pitchers: that Max Scherzer and Anibal Sanchez had been their best pitchers, that Rick Porcello has pitched quite well, that Drew Smyly is fitting in nicely in the Detroit rotation, and that Justin Verlander is struggling mightily.

While the numbers I came up with using ACR passed the eye-test, they still lacked context. I needed to know the Ace Composite Rating for all starting pitchers in MLB before the statistic could really be useful to baseball fans or fantasy owners. Now that we've arrived at the All Star Break, it seems like a perfect time to find out how all those pitchers stack up thus far.

Using data from Baseball-Reference I pulled the numbers from the first half of the season on all starting pitchers with seven or more starts. The calculation looks like this: ACR = (ERA + H/9 + HR/9 + BB/9 - K/9 - IP/GS) *-1.

I purposely avoided using any sabermetric numbers in the calculations for ACR because I wanted the final number to be accessible for average baseball fans and useful for fantasy baseball owners.

These are the top 25 starting pitchers in all of Major League Baseball through the first half of the season based on Ace Composite Rating.

Screen Shot 2014-07-14 at 5.55.06 PM

If you're interested, you can see the how the rest of the starting pitchers in MLB stack up in terms of Ace Composite Rating right here. Be warned -- this chart is enormous.

If you're not interested in wading through the entire chart, let me break it down for you. It turns out that the league average ACR for all starting pitchers with seven or more starts comes out to -3.16. That means that there have been 90 "above average" starting pitchers in all of MLB thus far. Once the ACR reaches the break-even point of 0, we're looking at about the best 33 starting pitchers in MLB, roughly the top 20%; meanwhile, the top 10% of starting pitchers all hold an ACR of 1.75 or better. And Clayton Kershaw is, well... on another planet.

To put it more simply, let's say this:

  • A pitcher with an ACR below -6 is a bad pitcher.
  • A pitcher with an ACR below -3 is, well, not that great.
  • A pitcher with an ACR of -3 is an "average" pitcher.
  • A pitcher with an ACR of 0 is a very good pitcher.
  • A pitcher with an ACR of 1.75 or better is an elite pitcher.
  • A pitcher with an ACR of 3 or better is an indisputable "ace."

As far as Tigers pitchers are concerned, you can see from the chart above that Max Scherzer has been the 23rd best pitcher in all of MLB in terms of ACR, which puts him in the top 13% of all starters. Here is a look at how all five men in the Tiger rotation have fared over the first half, along with their overall ACR ranks out of 173 qualifying pitchers.

Screen Shot 2014-07-14 at 6.24.23 PM

I was actually surprised to see Max was only 23rd best overall in terms of ACR -- I would have thought he would rank higher on the list. Still, it's not too shabby to be considered among the top 13% of pitchers in all of baseball. Additionally, if we take out Jose Fernandez, who is done for the season, and possibly Jesse Hahn, who has the smallest sample size of any pitcher in the top 25, Max moves up the chart a little bit. I don't know. Call me crazy, but I'd take Max Scherzer on my team any day over guys like, say, Josh Beckett or Michael Wacha, even if ACR says they're the better bet.

Anibal Sanchez nearly cracks the top 20% of all pitchers in MLB. Honestly, if not for his start on July 5 vs. Tampa Bay in which he allowed 7 earned runs, Anibal's ACR would probably be above the break-even point. I'm fairly confident that Sanchez will find himself on the plus side of zero before the season is over.

My gut tells me that Rick Porcello has been better than average -- and the fact that he was included in the All Star Game Final Vote seems to speak to that as well. But in terms of ACR, Porcello is barely better than league average. My (and most people's) perception of Porcello was likely aided by his back-to-back complete game shutouts that came right before the final vote was conducted. His best performances were fresh in the minds of baseball fans, who had forgotten about the time he allowed 7 earned runs against Texas on May 24. Still, I think Rick Porcello belongs in the discussion, if not in terms of ACR, then certainly in terms of ACR+, which includes all the same numbers as ACR but also considers complete games and shutouts. But we'll talk about that another time.

With an ACR of -5, Drew Smyly is a bit below the league average. But when you're talking about a guy who is working his first season in the starting rotation, and who was thought of as the Tigers' fifth starter when the season began, "a bit below league average" is more than acceptable. I'll take it. In fact, Smyly has been the Tigers' fourth best starter overall. What a pleasant surprise.

As for Justin Verlander... well, in terms of ACR, he is flirting with the border of bad pitcher territory. In fact, at 124 out of 173, he's in the bottom 18% of all MLB starters through the first half of the season. If his last few starts are any indication, though, Justin could see those numbers improve as the second half gets underway. At the same time, Justin's biggest issue over the last couple of seasons has been his inconsistency. Sure, he could go out there in his first start after the break and throw 8 shutout innings with 10 K. But he could also go out there in his very next start and get hammered for seven earned runs, like he did in back-to-back starts against the ChiSox and the Royals in June. It's frustrating. But all that frustration tends to go away in a hurry when JV turns on the postseason magic.

Eight of the nine starting pitchers on the American League roster for the All Star Game are in the top 25 of MLB in terms of ACR, the lone exception being Mark Buehrle. In the National League, there were several replacements due to injuries and due to selected pitchers having pitched recently. Still, of the eight starters who were voted in, seven were in the top 30 of MLB, with the lone exception being Madison Bumgarner. With all those great pitchers, this year's All Star Game should be a fun one to watch.

Enjoy the game tonight, and enjoy endure the next several days with no baseball. And, as always, go Tigers!

This is a FanPost and does not necessarily reflect the views of the <em>Bless You Boys</em> writing staff.

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