Gene J. Puskar/Associated Press

Yu Darvish was outstanding his last time out for the Chicago Cubs. Starting against the Pittsburgh Pirates on Friday, he allowed only two hits, one walk and zero runs over six innings.

Yet after he did so 21 times through his first five major league seasons, it's telling that this was only the first time Darvish logged at least six shutout innings through the first two seasons of his six-year, $126 million deal with the Cubs.

In fairness, the 32-year-old right-hander is just one of many problems plaguing the North Siders. His 4.72 ERA is but one black mark on a pitching staff littered with underachievers. And despite strong performances by Javier Baez, Kris Bryant, Anthony Rizzo and Willson Contreras, the Chicago offense has been feast-or-famine.

The Cubs' first-place standing in the National League Central has much to do with the mediocrity of the division. Their 50-44 record marks yet another backward step from their 2016 peak, which consisted of 103 wins and a long-awaited World Series title.

In the face of all this, president of baseball operations Theo Epstein on July 3 threatened drastic action ahead of the July 31 trade deadline on 670 The Score:

"I don't think sitting on our hands is really a viable option. We want to be in a position to have enough belief that we're looking to aggressively add and sort of polish up what we think can be a championship team. If we're not, that means this stretch of bad play has continued. And if this stretch of bad play continues, then certainly a ton of change is in order."

It's doubtful Epstein would completely break up the band, but there are parts of it that could go.

Joe Maddon, who's been managing the Cubs since 2015, is on the hot seat. The same goes for core players such as Kyle Schwarber and Albert Almora Jr., who might be offered in trades. Alternatively, Epstein may seek to clear some payroll by dealing Cole Hamels or even Jason Heyward, whose $184 million contract finally looks like something other than an utter disaster.

But if there is one guy the Cubs are likely stuck with, it's Darvish.

Paul Beaty/Associated Press

Contrary to what Captain Hindsight may be saying in the background, the Cubs' signing of Darvish wasn't an obvious mistake from the beginning.

At the time, they were coming off a season in which their starting rotation had regressed from a 2.96 ERA in 2016 all the way to a 4.05 ERA. As a strikeout guru who was fresh off his fourth All-Star season, Darvish was a natural solution to the problem. By the Cubs' standards, he was also affordable.

Still, his capacity to remain healthy was in doubt by way of his history of heavy workloads both in Japan and the United States as well as by his Tommy John operation in 2015. And despite his track record, his capacity to pitch effectively was called into question by two brutal turns for the Los Angeles Dodgers in the 2017 World Series.

As if on cue, Darvish made only eight starts in 2018 before elbow and triceps injuries sidelined him for the rest of the season. He also put up a 4.95 ERA when he did pitch, but the Cubs could at least reason then that better health in 2019 might lead to better pitching.

Darvish is indeed healthy, and there are extents to which he still looks like a top-of-the-rotation starter. He's whiffing 10.4 batters per nine innings, and even his hard contact rate is well-below-average. He certainly still has a live arm. Just ask the three guys who got dinged by a 99 mph heater out of his hand in April:

But while this might seem to point to bad luck as the cause for Darvish's poor season, there are also his well-above-average walk (4.4 per nine) and home run (1.7 per nine) rates. And while it's better than most pitchers' strikeout rates, his 10.4 K/9 actually is the second-lowest mark of his career.

No single pitch of Darvish's is getting hit as badly as his four-seam fastball, which has yielded a .699 slugging percentage. A related story is the shrinking gap between his fastball velocity and the average starter's. It was 1.9 mph as recently as 2017. Now there's only a 1.2 mph difference between his 93.9 mph average and starters' 92.7 mph average.

Plus, even extreme heat doesn't matter much anymore. The .412 slugging percentage hitters have against 95-plus mph fastballs is easily the highest measured since 2008 (when data tracking began).

It's no wonder Darvish has cut down the use of his four-seamer from a peak of 39.0 percent in 2016 to 30.7 percent this year:

Image courtesy of BaseballSavant.MLB.com.

It's also easy to notice the downturn in Darvish's slider usage, which likewise seems motivated by vanishing effectiveness. Per Brooks Baseball, it doesn't have nearly as much horizontal or vertical break as it did in its prime. Go figure that hitters' slugging percentage against it has been on the rise.

Darvish's arsenal has thus gone from a majority fastball-slider affair to a more balanced four-pitch attack. It's far from a bad thing that his cutter—which is holding hitters to a .231 slugging percentage—plays a central role now. But he's never been much of a control artist, and his fallen strike-zone rate reflects the difficulty he's had rising to the task of gaining control over his new-look pitch mix.

Further, hitters haven't been as fooled by Darvish's altered approach as his strikeout and contact rates suggest. They're maintaining a patient approach against him, and they've doubled down with runners on base via a 44.5 percent swing rate—Darvish's career low.

That's feeding Darvish's ongoing struggles with men on (.809 OPS allowed this year), which are best reflected in his diminishing three true outcome rates in such situations:

Data courtesy of FanGraphs

The bright side is that Darvish is showing no ill effects from last year's injuries. But sans vintage versions of his fastball and slider, he can only be effectively wild rather than truly overpowering. With his 33rd birthday due up Aug. 16, it's doubtful as to whether he'll ever reclaim those two pitches.

At this juncture, the Cubs can probably only move on from Darvish in a bad contract swap or in a deal that requires them to pay down a huge chunk of his remaining salary. And that's assuming there are even takers out there, which might be assuming too much.

If so, the Cubs will just have to chalk up the Darvish gamble as a loss and pursue change in other ways.

Stats courtesy of Baseball Reference, FanGraphs, Baseball Savant and Brooks Baseball.