We'd say that Yasiel Puig is going to have a good year in 2018, except that he already had a good year in 2017. By hitting .263/.346/.487 (117 wRC+, where 100 is league average) along with a career-high 28 homers, he basically put up the same year that Francisco Lindor (.273/.337/.505) did. It was better than he'd been in either of the previous two years. If he did nothing but repeat it in 2018, the Dodgers would probably be happy.
But what if there's more? There might be more. Puig is, after all, still just 27 years old.
It starts by splitting his season in half. In the first half last year, Puig hit .251/.324/.453 (103 wRC+), which is fine, somewhat. There were 166 qualified hitters, and on a rate basis, that mark was tied for 98th, which means about 60 percent of hitters were doing better. It's not terrible, but it's not great, either.
In the second half, that jumped to .278/.374/.533 (136 wRC+), which is much more than fine. Of the 162 hitters who qualified in the second half, Puig was 26th, or in the top 20 percent. He hit better than Jose Ramirez, or Anthony Rizzo, or Cody Bellinger, and he followed it up by hitting .414/.514/.655 in the first two rounds of the postseason before struggling against the Astros' outstanding pitching staff in the World Series.
That Puig, if he were able to keep it up over the course of a season, would be elite. The second-half Puig increased his walk rate by more than two points and dropped his strikeout rate by three points. He lowered his ground-ball rate by seven points, and upped his hard-hit rate by five points. It's what you want. You saw the results; he was the Dodgers' best second-half hitter in 2017.

But we know enough to understand that you can't simply look at second-half numbers, dismiss anything before that and assume that's the player you'll see going forward. It doesn't work like that, especially for a player like Puig, who hasn't exactly proved that consistency is his strong suit.
So instead of saying that Puig will definitely continue his second-half slugging ways, let's talk about how he did that, and one thing he does that might be special enough to focus on improving for the upcoming season.
To that end, let's start with a leaderboard. It's got a lot of hitting studs on it. It's also got Puig. 
Puig Smashes In the Air With the Best In the Game
(Highest Expected wOBA on Hard-Hit Batted Balls in the Air, 2017)
1.163 -- Aaron Judge
1.131 -- Giancarlo Stanton
1.102 -- J.D. Martinez
1.098 -- Puig
1.073 -- Chad Pinder
1.049 -- Miguel Sano
1.039 -- Gary Sanchez
1.030 -- Michael Trout
1.028 -- Justin Bour
1.026 -- Scott Schebler
Defined as above 95 mph and above 10 degrees. MLB average: .848.
That's a little complicated, so let's make it simple. To begin with, any power list that starts with Judge, Stanton, and Martinez is a list you want to be near the top of. Puig is fourth. He's ahead of Trout, the best player alive. This is a good start.
Here's what that list is really saying: "When a player hits the ball hard in the air, who is doing it in a way that is expected to lead to the most production, based on exit velocity and launch angle?" We have 218 qualifiers, so he's in the top 2 percent. That's extremely good. If we look at "actual" production rather than "expected," Puig is still in the top 13 percent; while he wasn't really lucky or unlucky, we prefer the expected view, because you still want to give a hitter credit for a ball struck like this, even when Odubel Herrera turns it into an out.

The point here is simple: Not every player has the skill to hit the ball hard in the air. Not every player should try. This isn't a one-size-fits-all solution. Puig, however, based on what we saw last year, might fit into the category of a player who ought to do it more. While his expected outcomes were elite, the frequency wasn't. Of those same 218 hitters, Puig's rate of putting hard-hit balls in the air was just 176th, or in the bottom 20 percent.
Puig knows that, for what it's worth, memorably telling a local paper last year that he "thinks about putting the ball in the air, or else I'm going to have no money in my pocket." He put 51 percent of his batted balls on the ground in the first half but improved to 44 percent in the second half -- well better than his career mark of 49 percent.
So that tells us something about what Puig might want to do more of going forward. What about the steps Puig took to get different results last year? Puig has never been known as a terribly patient hitter, yet he started to do something interesting in the second half. After an entire career of routinely swinging at the first pitch -- he did so 43.1 percent of the time from 2013-16, well above the Major League average of 27.9 percent -- he just … stopped.

After again posting higher-than-average first-pitch swing rate in the first half, 36.5 percent, Puig dropped that rate down to 26.9 percent in the second half. This doesn't, by itself, make him a good hitter. In fact, we often recommend that hitters be more aggressive against first pitches, if they're hittable. But for Puig, given his reputation, pitchers had stopped throwing him hittable first pitches. In the first half, nearly 90 percent of qualified hitters saw more first pitches in the strike zone or on the edges than Puig did. Another way of saying that is that pitchers figured he'd go after anything with an empty count, so they stopped giving him anything good. He noticed.
Puig adjusted, and that's really the point here. He has shown he can hit the ball hard in the air as well as the best in the game, if not as often as they do, so far. He's shown he can exhibit plate discipline when he wants to. We've seen him crush for months at a time, both as a rookie and last summer. For all his ups and downs, the capacity to change is still there. If it all comes together at the same time, the capacity for Puig to dominate is still there, too.