Which 2017 breakout sluggers should we buy going forward?

We’re in the midst of an unprecedented home-run boom in Major League Baseball. Want proof? First, we’re on pace to shatter the single-season record for home runs. Second, MLB players have already combined to hit more homers this year than they did in the entire 2014 season. It’s Aug. 10.

More than the sheer number of long balls being hit (or even why this is happening), the most fascinating element of this power surge is how all those home runs have been distributed. Despite the league-wide power explosion, MLB’s current long-ball leader (Giancarlo Stanton) is on pace to hit 55… a splendid season, but still well short of Roger Maris, Sammy Sosa, and Mark McGwire, let alone Barry Bonds. Only one other player (Aaron Judge) is on pace to top 50.

Instead, we’ve seen a passel of players boost their home-run totals with many taking aim at career-high numbers. Of those breakout guys, the most intriguing is a group of players you’d never, ever think of as star sluggers: Justin Smoak, Brett Gardner, Logan Morrison and Yonder Alonso.

Smoak is the name you know, of course. The 11th-overall pick in the 2008 draft, he was hyped as a future hitting star from the moment he started his professional career. It just took forever to get there.

In his early minor league days, Smoak was an on-base machine, spraying line drives all over the park and drawing tons of walks, albeit without a ton of power. From the moment he debuted in the big leagues, that skill set flipped, with Smoak striking out a lot more often, swinging for the fences, and frequently threatening the Mendoza line.

All of that’s changed this season. Smoak, as well as key Jays personnel like general manager Ross Atkins, have spoken at length about the mental adjustments the first baseman has made, which include seeing a sports therapist so he could stop being so hard on himself for his failures. On the field, the results have shown up in his batted-ball profile.

Unlike many of his power-breakout compadres, Smoak hasn’t suddenly started uppercutting the ball far more often, hitting more flyballs and thus more homers as a result. What he has done is make more hard contact than ever before. Combine hard contact with hitting two-thirds of your balls in play for flyballs and line drives (Smoak ranks seventh in the American League in line-drive rate), and you’re going to get some great results.

In Smoak’s case, you’ve got the 31 home runs, well past his career high of 20 and also the sixth-highest total in the majors. But you’ve also got career highs in virtually every other category — his .297 batting average and .376 on-base percentage dwarf his career bests of .238 and .334 back in 2013.

There’s going to be some regression in 2018: Only Jay Bruce has hit more wall-scraper home runs this season, and expecting any hitter to keep sneaking balls just barely over the wall is a fool’s errand, even when those balls are juiced. Still, Smoak hitting the ball more often than ever before, roping liners like he did in the minors and tapping into his power potential, while also swinging at fewer pitches out of the zone and swinging and missing less often than he has in years… all of these factors bode well for continued success beyond 2017.

When it comes to future success, Gardner and Morrison fall somewhere in between the buy and sell categories.

At 5-foot-11 and 195 pounds, Gardner might be the smallest of baseball’s power breakout brigade. Long far more known for his speed than his power, he once swiped 49 bases in a season, but topped out at 17 homers… taking a full 636 plate appearances to get there in 2014.

With more than 4,000 big-league plate appearances heading into the season in which he turns 34, you’d figure that whatever we’d seen from Gardner was what we were going to get this year; if anything his advancing age combined with the Yankees’ stockpile of young talent made you wonder if he might see less playing time this year.

Instead, Gardner’s already set a new career high with 19 bombs. His plan of attack has been simple: Hit the ball in the air, and aim for Yankee Stadium’s ludicrously short porch in right — and right-centre — field. Gardner’s flyball and pull rates are basically identical to his 2014 marks.

The difference this year likely comes down to a bit of luck, and the juiced ball, which has done wonders for so many players you’d never expect to go on a power binge. If MLB doesn’t order the seams raised and the cores deadened in these juicy baseballs, Gardner could conceivably hit a bunch more roundtrippers in 2018; the lefty-swinger has pulled every single one of his home runs this season, many of them right near the 314 sign in right, so he sure as hell knows what he’s doing.

Source: FanGraphs

You can trace Morrison’s ascendance, meanwhile, directly to a huge spike in flyballs. The Rays first baseman came into this season lofting flyballs less than 37 per cent of the time during his seven-year major league career. This season: a massive 46.8–per cent rate that’s seventh-highest among all AL batters.

In the same way that pitchers have started challenging Yankees mega-slugger Aaron Judge with high fastballs and making him whiff, pitchers could start climbing the ladder with Morrison, making it more difficult to unleash powerful uppercut swings that launch balls out of the park.

But if Morrison can respond to that inevitable change of pitching approach by working counts and drawing walks, he might force pitchers to eventually give in. That could lead to more dingers for the about-to-turn-30 non-slugger whose previous career high for homers in a season was 23 back in 2011.

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The player you short is Alonso. If many of this year’s other power surgers boasted moderate totals for their previous career highs, Alonso profiled like a banjo hitter, never hitting more than nine in a single campaign. Early this season, he made good on his promise to swing for the fences more often, ranking among the league leaders and hitting a boatload of homers as a result.

To wit: In the first half of this season, Alonso batted a red-hot .275/.372/.562, pummelling an incredible 20 home runs. Alonso’s second half, on the other hand, has looked pretty familiar:

Yonder Alonso AVG OBP SLG AB/HR
Pre-2017 0.269 0.334 0.387 39.9
2017 second half 0.214 0.329 0.343 35.0

Throw in Alonso being tied with Smoak for second in the majors with 12 barely-over-the-fence home runs, and the Mariners might not have gotten much when they got him from the A’s on Sunday.

Predicting which 2017 power poster boys will sustain their success going forward is far from an exact science. Youth and a strong minor league track record for homers are a great sign, which is why you should get excited about Rangers beast Joey Gallo. Hitting two homers for every five flyballs you hit is a completely unsustainable rate for even the strongest power hitters, which is one of several reasons that Judge has cooled off considerably over the past few weeks (with his still MLB-leading home run-per-flyball rate cooling off at the same time).

An in-season slowdown like Alonso’s should make you trust thousands of previous plate appearances over several years, rather than a couple hundred in a couple months. But just as these hitters (along with Mike Moustakas, Zack Cozart and other sudden swatters) made adjustments to become home-run threats, further adjustments will likely determine how well they fare in the future.

That, or Major League Baseball could stop issuing non-denial denials about the juiced balls, return them to their previous state, and return the game to a time before every medium-hit flyball soared into the stratosphere. Either way.