Here is a rare opportunity for the non-Marty McFlys among us to look back on something that hasn't even happened yet. Let's go back to the future to discuss the 2018-19 free-agent mega class that never was.
Back around the time of the 2015 Winter Meetings, a free-agent class still three years away was, unusually but understandably, a topic du jour in Major League Baseball. It was hard not to be intrigued by a group that was set to include such bold-faced names as Bryce Harper, Manny Machado, Clayton Kershaw, Josh Donaldson and many others.
"But," an American League general manager cautioned at the time, "several of these guys may get injured or sign extensions and drastically change the dynamic of the class. So it can be very different than what it appears to be now."

Ain't that the truth?
The upcoming free-agent period is still special, because it is still set to include two 26-year-old franchise-changers in Harper and Machado. But as a different AL executive observed the other day, "How many teams, realistically, are in those markets?"

Indeed, regardless of how much those guys command, it's not exactly going to be a wide swath of squads with the financial freedom to snag one of those two superstars. The Dodgers, Yankees and Giants pointedly put themselves under the luxury tax threshold for 2018 to reset their penalties and, potentially, get in on the bidding. Maybe the Cardinals or Cubs get involved. Maybe the Red Sox, but they're already north of the threshold. The Phillies, Braves and White Sox could be ready to spend big. The Nationals could re-sign Harper.
That's probably about the size of it. "Harper and Machado" is a movie that will only screen in selected cities.
But this offseason's class was supposed to have something for everyone. It was supposed to be so overloaded with star power that even the spillover would include tangible talent. Instead, after Harper and Machado, it all looks pretty ... normal.
What happened? The realities of life and baseball happened:
• We tragically lost the great and young Jose Fernandez. He was to be the third 26-year-old superstar eligible for free agency after 2018.
• Kershaw, David Price and Jason Heyward, all of whom have opt-outs after 2018, have had experiences that make it increasingly doubtful that any of those opt-outs will be exercised. As great as Kershaw's career has been, the reality is that he's now a 30-year-old with what can only be described as a chronic back issue (he's on his third back-related DL trip in as many years). Price has been fantastic in the wake of his carpal tunnel issues last month (2.87 ERA in his past five starts), but his three years with the Red Sox have featured a modest 3.88 ERA and an elbow issue that limited him to less than 75 innings last year, so his ability to better the $127 million he's owed from 2019-22 if he doesn't opt out is very much in question. And Heyward? Let's just say that teams wouldn't be talking themselves into the value of his defense and the upside in his bat in the offseason before 2019 the way the Cubs did in the offseason before 2016.
• Dallas Keuchel has come down from his Cy Young height in 2015. He pitched really well around a neck issue last season, but, 13 starts into '18, he's sitting on a 4.13 ERA.
• Former MVPs Donaldson and Andrew McCutchen have been less valuable. Donaldson, 32, is expected to be activated by the Blue Jays on Friday, but he's had three DL trips related to his calf and shoulder since the start of 2017, and he's got an un-Donaldson-like .234/.333/.423 slash line in 36 games thus far this season. The 31-year-old McCutchen's combined 112 OPS+ over the past three seasons is a shadow of the 157 mark he compiled in the four seasons prior. Fellow pending free agent Adam Jones, 32, is another example of a player whose impact falls in the realm of "good but not franchise-altering" now that he's north of 30.
• A.J. Pollock and Daniel Murphy, who have played like MVPs when healthy, have struggled to get or stay on the field. Pollock has played just 164 games since the start of 2016 and is out with a fractured thumb. Murphy is coming off microfracture surgery on his right knee and has yet to play a game this year (and he'll be 34 in '19).
• Charlie Blackmon pulled out of the market in April. He got a six-year, $108 million extension offer from the Rockies entering his age-31 season and took it.
• "The Dark Knight" went dark. Matt Harvey has shown some flashes of potential with the Reds but, ultimately, he's got a 5.78 ERA since the start of 2016, and it's entirely possible that Tommy John surgery and then thoracic outlet syndrome surgery have robbed him of the ability to be a premier pitcher.
• James Dozier, Marwin Gonzalez, Ian Kinsler and Thomas Pomeranz, all of whom would have rated as quality options in the not-too-distant past, are off to slow starts.
• Andrew Miller has been compromised. The guy who got teams rethinking the way they deploy their relief weapons could use some relief from right knee ailments that have led to three disabled-list trips in the past 10 months (in addition to a hamstring-related DL stay).
• And of course, free agency itself changed. After the austerity that enveloped the 2017-18 market, it's frankly difficult to know what anybody is worth anymore. Teams are less inclined to pay for sluggers now that almost everyone hits for power, and they are also valuing prospects and Draft picks like never before, making it tougher for free agents on the other side of 30 to get deals they once did.
I don't know about you, but I could use some good news after all of the above. So here are a handful of walk-year guys who have, in some cases unexpectedly, greatly improved their free-agent values in 2018:
Patrick Corbin, LHP, D-backs: He came into 2018 with a career ERA+ just 4 percent better than league average. But through 13 starts in '18, Corbin has been 50 percent better than league average.

Michael Brantley, OF, Indians: A few months ago, you would have put him in the uninspiring portion of this program. Brantley played just 101 games total between 2016-17 because of shoulder and ankle woes. But even at age 31 and with an extensive injury history, his 89 percent contact rate in a rebound season at a time when the game has gone K crazy could make him a really interesting free-agent case.
Charlie Morton, RHP, Astros: All the strides we saw from him last year, en route to World Series Game 7 hero status, have been built upon in his walk year. Houston helped Morton tap into repertoire tweaks that, even entering his age-35 season, could get him paid big bucks.
Adam Ottavino, RHP, Rockies: He's currently on the shelf with an oblique issue, but Ottavino is striking out 45 percent of opposing batters, which, even in this high-strikeout society, stands out. Like his Colorado mates Wade Davis and Bryan Shaw last offseason, Ottavino is in good position to get P-A-I-D given the money teams are now willing to invest in their bullpens.

Kelvin Herrera, RHP, Royals: He has bounced back from a 1.35 WHIP in 2017 to put together a season on pace to be even better than anything we saw from him during the Royals' 2014-15 run (0.79 ERA, 0.71 WHIP). Before Herrera gets paid, he'll get traded. The calls to Kansas City from execs on contending clubs have already begun.
Nick Markakis, OF, Braves: Nobody's going to back up the Brink's truck for a 35-year-old in this day and age, but Markakis (.328/.392/.498) nonetheless picked a good time for a surge in extra-base-hit production.

So, yes, the 2018-19 free-agent class will still be interesting. And the Machado and Harper sweepstakes will be scintillating. But on measure, this isn't shaping up to be the seismic offseason we envisioned. To quote Yogi Berra, "The future ain't what it used to be."