Last winter, coming off the best season of his career, Yoenis Cespedes hit the free-agent market, and promptly heard crickets. He watched David Price and Zack Greinke break $200 million in early December, and then saw Jason Heyward set the market for outfielders with a $184 million deal a week later. And then he sat and watched a bunch more pitchers get paid, while he, Chris Davis and Justin Upton sat around waiting for offers that never came. Finally, in January, all three eventually found homes, but Cespedes was unable to land the big deal he was looking for, instead taking a three-year deal from the Mets that gave him the chance to hit the market again this winter, if he so chose.

A quarter of the way through the 2016 season, Cespedes opting out of the last two years of the deal is now a foregone conclusion; the only way he wouldn’t hit the market this winter is if the Mets re-do his deal before he gets there, or if he blows out his knee between now and October. Cespedes has not only carried over last year’s second half surge, but he’s even somehow building on it.

After getting traded from Detroit last summer, Cespedes hit .287/.337/.604, launching 17 homers in 57 games. The power spike was something unseen before from him, and so he went from being a good player with nice power to performing like a great player with elite power. But guys do weird things in half-seasons, and there was no real reason to think Cespedes had suddenly morphed into one of the game’s best power hitters. And the skepticism about his new-found power was one of the reasons the free agent market didn’t treat him too kindly, but Cespedes is helping show that the surge wasn’t just a two-month fluke.

The rolling-average of his ISO shows that Cespedes had pretty normal peaks and valleys in his Oakland days, bouncing mostly between .100 and .300, which is what you’d expect from a guy with a .200ish ISO. But over the last four months of baseball, his spikes have reached the kind of levels you’d see from Giancarlo Stanton on a hot streak, and his valleys have been where his baseline used to be.

So, what changed? Well, in an overview of Cespedes and his free agent stock from last winter, Mike Petriello gave us this chart.

In New York, Cespedes started elevating the baseball in a way he hadn’t earlier in the season, and the result was that balls started flying over the fence. His average launch angle so far in 2016? 17.4 degrees. A one-month spike is now a three-month trend, and the spike in balls in the air is one of the primary reasons why Cespedes is producing at an elite offensive level.

But the remarkable thing isn’t so much that he’s been able to hit the ball in the air more often; lots of guys could do that by changing the angle of their swing. But the downside to an uppercut swing is that it also usually leads to an increase in whiffs; there’s a reason why guys like Chris Davis run strikeout rates over 30%. Cespedes, though, hasn’t really sacrificed any contact while finding this power stroke.

Since September 1st, lining up with this change in launch angle, Cespedes has made contact on 86.8% of his in-zone swings and 76.3% of his swings overall. For his career up through August 31st, Cespedes had made contact on 85.3% of his in-zones wings and 76.5% of his swings overall. Cespedes has somehow pulled off the pretty rare trick of adding power without having to swing and miss more often, and that has made him a substantially better hitter than he was earlier in his career.

Guys who hit for elite power while running these kinds of contact rates are almost universally elite hitters. From 2011-2015, here are the hitters who ran an ISO over .230 and an in-zone contact rates over 85%.

And now, pitchers are adjusting. During his career, pitchers have thrown about 46% of their pitches to Cespedes in the strike zone, a few ticks below the average, and about what you’d expect for a free-swinger with some power. This year, pitchers are throwing only 44% of their pitches to Cespedes in the zone, so even though he’s not getting any more selective, he’s now getting pitched in a way that allows him to occasionally draw a walk as well. Last year, Cespedes drew 19 walks in the first four months of the season before being traded to New York; he’s already drawn 17 in the first six weeks of 2016.

Cespedes probably won’t keep walking in 10% of his plate appearances, but with pitchers realizing that they need to be a bit more careful with him than they used to, he’s likely a better bet to post higher OBPs going forward than he has in the past. He’s never going to morph into an Ortiz or Goldschmidt in terms of selectiveness, but walks aren’t just about taking pitches; they’re also about scaring pitchers, and Cespedes is doing plenty of that right now. Even without a change in approach, his increased power should also bode well for some gains in walk rate.

Since joining the Mets, Cespedes has basically played like a +7 win player, putting him in the upper tier of Major League players. That remains an unsustainable level over the long term, and he won’t keep hitting for this kind of power all season, but even with an expected level of regression, Cespedes still looks like a fantastic player. Our rest-of-season forecasts call for Cespedes to produce an additional +3.2 WAR over the remainder of the season, putting him in the same tier as Francisco Lindor, Mookie Betts, and Starling Marte. And that’s with Steamer still expressing plenty of skepticism about his power spike; ZIPS buys into the increase in power, and puts Cespedes at +3.8 WAR rest-of-season, putting him in the same group as Buster Posey and Nolan Arenado.

Like with Daniel Murphy, we’re now past the point of this being just a hot streak. Cespedes has made structural changes to his game, and the power spike without a compensating increase in strikeouts has made him an offensive force to be reckoned with. Toss in the defensive value and the baserunning, and it’s probably time for the league to stop being skeptical of Cespedes as a top-tier position player. When he hits the market again this winter, he should get paid like an elite player, because it’s now pretty clear that he indeed is one.