I better write something about Wade Davis since the Royals' setup guy is having a terrific season -- 8-2, 0.77 ERA, five runs allowed with 87 strikeouts and just 28 hits in 58.1 innings entering Thursday. He hasn't allowed a run in his past 25 appearances, a span of 24.2 innings.

As unhittable as he's been, I just learned this from a comment on a Joe Posnanski story about Alex Gordon's MVP chances:

MoreHRs&LesNorman August 28, 2014 at 10:17 pm Joe–Please find video of the two “extra base hits” Davis has given up. The first was hit like a single but hit to left-center. It didn’t get to the wall, but it was enough for a double. The second was an opposite field bloop hit against the shift. Davis has not allowed a ball over the wall, a ball hit to the wall or a ball hit up the line ALL SEASON!!!

Sure enough, Davis has allowed just two doubles, no triples and no home runs. I went to the video.

On July 31, Kurt Suzuki lined an 0-1 curveball down the left-field line that Gordon scooped up before it hit the wall, but deep enough that Suzuki cruised into second.

On Aug. 15, Joe Mauer sliced a blooper right on the left-field foul line. Gordon actually made a diving effort and got there, but the ball popped out of his glove when it hit the turf.

So two doubles, only one struck well. Pretty amazing. I'm sure he's allowed other well-struck balls, of course, but only Suzuki's went for extra bases.

Overall, Davis has allowed a batting average of .139 and a slugging percentage of .149, giving him an "isolated power" allowed figure of .010. I assumed that would be the lowest ever (minimum 50 innings), but it's not. A reliever named Frank Williams for the 1986 Giants had an isolated power allowed of .006. In 52.1 innings, Williams allowed 35 hits -- just one for extra bases, a double. (He also allowed just one stolen bases while nine guys were caught stealing on his watch ... wow.) The Giants thought so much of his performance they traded him to the Reds in the offseason for outfielder Eddie Milner.

(Williams' story is interesting but sad. He started one game in his career ... and threw a shutout, as a rookie in 1984. According to this story by Tom Hawthorn of the Toronto Globe and Mail, Williams' best pitch was a slurve of sorts that he gripped deep in the palm of his hand. You can see from the baseball card photo in that story that Williams threw from a sidearm or three-quarters delivery. He took part in tough-man boxing matches in Idaho in the offseason. After his career ended, he explored his Native American roots, but his life fell apart with drug and alcohol use and the death of his twin brother and he eventually ended up living on the streets of Victoria, B.C., and died in 2009.)

Back to Davis. The lowest isolated power figures going back to 1957, from the Baseball-Reference.com Play Index:

1. Williams, .006

2. Davis, .010

3. Jim Johnson, 2008 Orioles, .016

4. Kevin Cameron, 2007, .023

5. Rob Murphy, 1986 Reds, .024

Nearly all of the pitchers at the top of the list are relievers. The only full-time starter to crack the top 75 is Nolan Ryan, in the 1981 strike season, pitching for the Astros. He allowed 99 hits that year in 149 innings -- just 10 for extra bases (seven doubles, one triple, two home runs). His ISO of .028 ranks eighth.

Davis' comeback from a bad 2013 season is a testament to his mental toughness as well -- he was one of the least valuable players in baseball last year when he went 6-10 with a 5.67 ERA in 24 starts before being mercifully moved to the bullpen, where he had excelled with Tampa Bay in 2012.

Obviously, his stuff plays up much better in shorter stints. I thought the Royals made the right decision a year ago to give him one more chance at starting, although Ned Yost waited too long to remove him from the rotation. Now he's one part of that awesome trio of Kansas City relievers, along with Kelvin Herrera and closer Greg Holland, a key reason the Royals lead the AL Central.