Question 4: Is Donaldson that good on D?

This week, I started a '10 questions' exercise by asking where Robinson Cano's power went, what's wrong with Justin Verlander and then whether or not Freddie Freeman is a .300 hitter.

Question No. 4: Is Josh Donaldson that good on D?

Before going 3-for-6 over his past two games, Oakland A's third baseman Josh Donaldson had been in a 3-for-45 slump. He's now hitting .254/.338/.484, a severe decline from the .280/.373/.552 triple-slash line he held on June 6.

Nonetheless, Donaldson still ranks first in the American League in Baseball-Reference wins above replacement (bWAR) at 4.6 -- ahead of Mike Trout's 4.4. He's third among AL position players in FanGraphs WAR (fWAR), albeit with a lesser total of 3.4.

So why does a guy who is hitting .254 and leading AL third basemen with 15 errors rank as the best player in the league, or one of the best?

We'll scoot past his offense quickly. Even with the recent slump, he's tied for 15th in the AL in weighted on-base average (wOBA). In weighted runs created (wRC+), which makes a home-park adjustment, he's 11th. So he's still been one of the most productive hitters in the league, and he's missed just one game.

But what helps separate him is his defense. Baseball-Reference uses Defensive Runs Saved, which calculates Donaldson at 17 runs above average -- that's the second-highest total in the majors at any position (behind Jason Heyward). FanGraphs uses Ultimate Zone Rating (UZR), which has Donaldson at plus-10.5 runs, the third-highest total of any player (behind Alex Gordon and Heyward; the two systems agree on the top three guys, just in a different order).

So even with all the errors, Donaldson rates as a terrific defender. He does pass the eye test. As I've written before, he's remarkably athletic for a player originally groomed in the minors as a catcher. Just to give a taste: Here's a great play, here's another one, here's a third one that led to a double play and here he is making a bare-handed play on a bunt.

Here's what got me when I was checking his stats: He's making 3.74 plays per game (assists plus putouts). This is the old stat Bill James called Range Factor. I realized that's a lot of plays per game. Manny Machado, for example, had a Range Factor of 3.05 last season and 3.12 in 2014, and he's a pretty awesome third baseman. Yes, Range Factor can be influenced by how many left-handers are on your staff, but that's still a lot of plays Donaldson is making. (The A's are first in the majors in innings pitched by left-handers.)

Baseball-Reference lists the yearly leaders in Range Factor per nine innings here. In the past 30 years, the only third baseman to crack 3.5 was Tim Wallach of the Montreal Expos in 1985 at 3.54. The leaders are usually around 3.0. The last third baseman to top Donaldson's 3.74 was Buddy Bell in 1982 at 3.86. That Texas Rangers staff had three lefties in the rotation -- Frank Tanana, Rick Honeycutt and Jon Matlack (part time) -- and averaged just 4.3 strikeouts per nine innings. The A's average 7.4 strikeouts per nine innings. The A's aren't an extreme ground ball staff -- they're 11th in the majors in ground ball percentage at 47.8 percent, less than one percent above the MLB average.

Overall, Donaldson's current Range Factor would be the eighth highest ever for a third baseman (Clete Boyer has three of the top seven).

Bottom line: Yes, Donaldson is that good on defense.