The Pittsburgh Pirates just had a terrible six days -- six days that might have signed and sealed their 2016 season. They went 1-5 on a trip to Milwaukee and Atlanta, two teams they needed to clean up against as they fight for a wild-card spot. Instead, they're 53-53 entering Friday, and while they're still only three games back of the second wild card, the Marlins, Cardinals and Mets are ahead of them, and the Rockies have tied them.

In the midst of all this, Andrew McCutchen was benched for the entire Braves series. The Pirates called it a mental timeout of sorts.

"He's tried a lot of things," manager Clint Hurdle told reporters. "This man's fought and shown up and done early work, late work, side work, video work. I just encouraged him, in some situations like this, what I've seen happen with good players, you just unplug them. The manager's got to do it. I'm just asking you to sign off on it."

McCutchen didn't want to sit but accepted Hurdle's decision.

"If I had my choice, I'd be in there," McCutchen told Rob Biertempfel of the Pittsburgh Tribune-Review. "But I'm all for my team, all for my teammates, so that's the reason I'm not going to mope about it."

So what's going on? It simply seems that something in McCutchen's swing or his approach is so messed up that he's simply not hitting the ball hard:

This is McCutchen's monthly exit velocity. Whatever reason the Pirates have for sitting him right now, I get it. pic.twitter.com/tuSP0C7bNs

— Mike Petriello (@mike_petriello) August 3, 2016

Exit velocity can certainly be affected by injury. Last August, Mike Trout's velocity went way down as he homered only once in the month, but there was a clear reason why: He'd hurt his wrist diving for a ball and played through the injury. Healthy again in September, his exit velocity returned and he hit home runs.

The Pirates and McCutchen both say there's not an injury involved with him, although he was bothered by a sore thumb earlier in the season.

So that leaves a 29-year-old perennial MVP candidate having a terrible season. McCutchen said people can get spoiled because of the years he has had, that he's capable of being "average." Actually, he hasn't even been average. His adjusted OPS and wOBA are both below the average National League hitter.

That's what's so odd about this. A superstar hitter doesn't usually go from superstar to suspect overnight, at least not when he's 29. From ages 25 to 28, McCutchen hit .313/.404/.523, with an OPS+ of 157. This year, while offense across the game has increased, he's down to .241/.311/.408, although he does have 15 home runs. His K rate is up and his walk rate is down. Pitchers no longer fear him and he's actually seeing more strikes than ever, with 51.4 percent of pitches to him in the zone compared to 47.2 percent last year.

To see how unusual McCutchen's season has been for an elite hitter, I checked hitters since 1950 who posted a similar adjusted OPS (thanks to the Baseball-Reference Play Index) from ages 25 to 28. McCutchen ranks an impressive 17th on the list, just below Albert Belle and Paul Goldschmidt, and tied with Fred McGriff and Miguel Cabrera.

Here's a table with the 10 players immediately above McCutchen and 10 (plus ties) below, how they fared at age 29 and their age the first time they had a sub-110 OPS+:

As you can see, McCutchen's bad season at age 29 is unprecedented for this class of hitter. The lowest figure other than McCutchen's 91 belongs to Norm Cash at 120, and he's kind of an odd case to begin with. His 25-28 OPS+ is propped up by one of the greatest fluke seasons of all time, when he posted a 201 OPS+ in 1961 (he hit .361, the only season above .300 in his career); Cash would later admit to using a corked bat that season. Anyway, his age-29 season was a poor one for him, although closer to what he did the rest of his career (he actually never fell below a 110 OPS+).

Even some of the low figures here were just down seasons. Carl Yastrzemski and Jim Thome, for example, bounced back to have monster seasons at age 30.

The most alarming comparison is Prince Fielder. He had a career 144 OPS+ through age 28. His age-29 season was his final one in Detroit, when he fell to .279 with a career-low 25 home runs. He was injured in 2014, had a bounce-back year in 2015 (although still just a 126 OPS+) and was injured again this year.

Ken Griffey Jr. was another guy who had seen his best seasons by age 29. His age-29 season was his last one in Seattle and he'd top that OPS+ figure only once more in a full season (144 at age 35), in part because of injuries.

But nobody is close to McCutchen's 91. Some of these guys never declined to that level. So what's going on? If McCutchen is just having one of those years, well, it's historically unique. That's why these guys were so good; they didn't have bad seasons.

Maybe McCutchen has let everything get in his head; that seems more plausible than a sudden loss of skill. There also could be an injury that the team hasn't disclosed; it certainly wouldn't surprise me if we hear something after the season.

Anyway, maybe the timeout will help, McCutchen clears his head and rips it up the final two months. Let's hope that's the case.