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Baseball is a turbulent sport. Every year, a handful of players seemingly come out of nowhere and post extremely successful seasons. Some of these players were once highly-touted prospects finally living up to their potential; others seemingly come out of nowhere to perform at elite levels. That said, very few players have truly consistent staying power.

In 2017, Aaron Judge, Anthony Rendon, Charlie Blackmon, Tommy Pham, Luis Severino, and Zack Cozart were among baseball’s biggest surprises. All players were in baseball’s top 30 players by fWAR for the first time sans Rendon, who hadn’t been since 2014. Judge led all of baseball with an 8.2 fWAR; Rendon posted a career-best 6.8 fWAR; Blackmon and Pham posted their first 6+ fWAR seasons at 6.5 fWAR and 6.1 fWAR respectively, while Severino broke out for a 5.7 fWAR and Cozart broke out for a 5 fWAR mark. While their 2017 seasons were remarkable, only three of these players have excelled in 2018: Judge, Rendon, and Severino. Charlie Blackmon, while remaining an above-average bat, has been abysmal as a defensive center fielder and has only posted a 0.9 fWAR through 73 games. Tommy Pham has been an above-average hitter, as well, but has seen his wRC+ drop from 148 in 2017 to 110 in 2018, and his fWAR stands at 1.4 through 70 games as a result. Meanwhile, Zack Cozart has been close to replacement level for the Angels: his on-base percentage has plummeted from .385 in 2017 to .296 in 2018, and his fWAR from 5.0 after 122 games to 0.4 after 58 games.

Not all breakout stars have staying power; many players simply have a “career year” before coming back down to earth. This begs the question: which 2018 breakout players are true stars and which will come back down to Earth? Let’s take a closer look at the numbers of the five players currently in MLB’s top 20 players by fWAR who have never posted a 5+ fWAR.

Trevor Bauer

Much like his teammate Corey Kluber, Trevor Bauer struggled in his first few seasons. He could not find his ground in the majors during limited starts in 2012 and 2013. From 2014 to 2017, he did not post an ERA below 4 and he looked like a middle-to-lower-end starter. That said, things have changed this year. As of June 26, Bauer is the only player to never post a 5+ fWAR season in the top 10 of the fWAR leaderboard and he has the second highest fWAR of any pitcher in baseball (only behind Max Scherzer’s dominant 4.6 fWAR over just 107.2 innings). His numbers are comparable to those of baseball’s very best pitchers, such as Max Scherzer, Justin Verlander, and Chris Sale, and his current fWAR (3.8) is an entire win higher than that of his rotation-mate Corey Kluber (2.8).

Bauer is not as reminiscent of Kluber as he is of the one pitcher better than him in 2018, however. Indeed, Trevor Bauer is following a Max Scherzer-like career trajectory. Putting aside their shared path from being a top Diamondbacks prospect to becoming an ace of an AL Central team, both were late bloomers who went on to exceed the ace of their rotation in their breakout season. In 2013, Max Scherzer finally flashed his full potential, winning the American League Cy Young award en route to a 6.1 fWAR season. While Scherzer had posted a 4.4 fWAR in 2012, however, Bauer posted a good-but-not-great 3.2 fWAR in 2017, so Bauer’s breakout is a bit more surprising than Scherzer’s in 2013. That said, both have had similar career trajectories. (Further, Bauer is only in his 27-year-old season, whereas Scherzer was 28 when he won the Cy Young in 2013).

The former #3 overall pick has a .302 opponent BABIP completely in line with his career .301 opponent BABIP, and while his home runs per nine rate of 0.42 may be unsustainable (his career rate is 1.01), his strikeout rates are up and his walk rates are down. Bauer has figured out something this year (and I don’t mean his research into conspiracy theories) and will continue to be a top-end starter moving forward.

Verdict: Fixture

Eddie Rosario

Eddie Rosario is in his fourth full season for the Twins and has ramped his production up to elite levels in 2018. While it’s true that Rosario hit 27 home runs for Minnesota last year, his on-base percentage still sat at .328 as he struggled to draw many walks. Interestingly, Rosario is walking at a lower rate in 2018 than he did in 2017 (down from a walk percentage of 5.9% to a 5.5% rate), but hey, if you can go from hitting .290 to hitting .320, that does not matter very much.

Rosario is having a career year and there is no doubt about it. A .320 average through 73 games is nothing to scoff at, and he is on pace to hit close to 35 home runs. The amazing thing about Rosario this year, however, is his knack for getting extra-base hits. While he is far behind his teammate Eduardo Escobar, who has an astonishing 33 doubles in just 71 games (the record is 67 by Earl Webb in 1931 for the Boston Red Sox), Rosario has knocked 21 doubles and a pair of triples to go along with his uptick in power. Rosario is on pace to post a 6.5 or higher fWAR this year, and that’s nothing to scoff at.

Looking at Eddie Rosario’s career thus far, it’s hard not to think of Anthony Rendon, who has posted two 6+ fWAR seasons along with a couple of low-to-middle-end starter seasons. That said, Rendon draws walks. He has a career walk rate of 10.2%, over twice as high as Rosario’s 4.6% rate. Rosario does have a couple of things going for him in his peripherals. His 16.8% strikeout percentage is a huge improvement on his 21.3% career rate and was already trending down when he struck out 18 percent of the time in 2017. Furthermore, his .342 BABIP in 2018 is high, but not too far from his .328 career BABIP. Rosario is a very good player, but he might not even hit 6 fWAR this season with his numbers coming solely from his hitting. Nevertheless, Twins fans should be very happy to have him.

Verdict: Fluke

Patrick Corbin

Patrick Corbin’s first complete season in 2013 felt like a sign of things to come. In his first full season, Corbin was an all-star, and he would have likely started the game had it not been at Citi Field, as he had an impressive 11-1 record and a 2.35 ERA entering the All-Star Break (instead, Matt Harvey earned the nod). Unfortunately, Corbin missed all of 2014 with a UCL injury. From there, he posted encouraging numbers in 85 innings in 2015 before going through a miserable 2016 season. He rebounded last year with his second 3 fWAR season and his first since 2013, and this year, he has nearly matched the mark with a 2.6 fWAR through 100 IP. Through perseverance and patience, Corbin has once again worked his way back to the ability he flashed in his 23-year-old season.

Through sixteen starts, Patrick Corbin has been absolutely dominant in 2018. In years past, Corbin has relied on his slider to get outs. In fact, using Fangraphs pitch values, Corbin’s slider has been worth 41.5 runs more than the league-average slider over his career, whereas his other pitches have all been worth negative runs…that is, until he evolved his sinker this year. Coming into 2018, Corbin’s sinker had been worth -5.1 runs compared to the league-average sinker, but this year, it has been his best pitch, being worth 11.9 runs above average. His slider has already been worth 9.9 runs, as well, and only his fastball and his newly-implemented cutter have been worth negative runs (his fastball sitting at a -1.0 mark and his cutter at a -0.1 mark, neither of which are bad whatsoever compared to years past). Corbin’s entire repertoire has reaped the benefits of his evolved sinker, and he has pitched at an elite level because of it.

Only 28 years old, Patrick Corbin is here to stay. He has elevated his ability to strike batters out, boosting his strikeouts per nine innings from an 8.30 career rate to an 11.61 rate in 2018. He has walked fewer batters, as well: his 2.43 walks per nine rate is quite a bit lower than his career rate of 2.66. And while it is true Corbin’s opponent BABIP of .273 is a decent amount lower than the career rate of .309, he is not stranding that many more baserunners than his career rate (76.5% in 2018 compared to a career rate of 72.8%) and he is allowing fewer than one home run per nine innings. Is the humidor in Chase Field helping? Probably. Regardless, Corbin has once again found his ceiling, and he should continue to post dominant numbers as long as he stays healthy.

Verdict: Fixture

J.T. Realmuto

The Miami Marlins are 32-47 entering play on June 26 and are the worst team in the National League (though the Cincinnati Reds and New York Mets are currently only a half-game better). While that is not a good record by any means, it is much better than anybody expected in March. The number one reason that the Marlins are exceeding expectations in 2018 is that they are keeping it Realmuto. That’s right: soon-to-be-all-star catcher J.T. Realmuto is baseball’s best catcher in 2018, and his 2.9 fWAR in 57 games is a full win better than Wilson Contreras’s 1.9 fWAR in 67 games. Realmuto will easily post his third straight 3.5+ fWAR season and is establishing himself as a superstar in 2018.

The most surprising part of J.T. Realmuto’s numbers is that he has only played in 57 games. He has made them count, however, as he has posted a .308/.367/.549 triple-slash, a 150 wRC+, and 10 home runs as a catcher. These are extremely gaudy numbers by catcher standards in 2018, and that is all in addition to Realmuto having a reputation as a very good defensive catcher. Sure, his .351 BABIP in 2018 will eventually come back down a little bit (though he has a career .325 BABIP), but Realmuto is a great hitter, a great fielder, and is even a good baserunner, which is extremely uncommon for catchers. He has been a very good catcher for three years now: in 2018, he simply decided to be the best.

The Marlins should expect a massive haul for J.T. Realmuto, as he has established himself as the best player in baseball at one of its most important positions. At only 27 years old, Realmuto is on pace to post his third straight season with a wRC+ above 105 and he has already posted his third straight double-digit home run season. He may not post offensive numbers like this going forward, but he has proven himself to be a top-end catcher and, therefore, is a franchise fixture.

Verdict: Fixture

Matt Chapman

The youngest player on the list and the player most heavily carried by his defense, Matt Chapman has already posted a 2.9 fWAR in 69 games in his 25-year-old sophomore season. He was quietly very impressive in 84 games for the Athletics, posting a 2.7 fWAR in 2017, but he shared the spotlight with fellow breakout rookie Matt Olson, who posted a 2.1 fWAR mark in just 59 games last year (who, may I add, had a .352 on-base percentage despite a .238 BABIP). While he is currently on the 10-day disabled list with a hand injury, Chapman has been brilliant in 2018 and should continue to be a defense-first star moving forward.

Matt Chapman is not the flashiest of hitters. His career .242 average over 153 games is mediocre at best, though he has a knack to draw walks: he walked at a 9.8% clip in 2017 and has boosted that rate up to 11.4% in 2018. He also has sneaky power, as he hit 14 home runs in 84 games in 2017 and has hit 10 home runs in 69 games in 2018. Over the course of a full season, Chapman could likely hit 25 to 30 home runs. With that many walks and that many home runs at third base, Chapman is overall a net positive offensive player.

While he is a patient but powerful hitter, Matt Chapman is best known for his fielding ability, and this is where his value really comes into play. Entering play on June 26, Chapman is baseball’s second-best fielder according to Fangraph’s defensive metric at 10.1 defensive runs above average (narrowly behind Tigers shortstop Jose Iglesias, who has been worth 10.3 runs in 75 games, and ahead of Angels shortstop Andrelton Simmons, who has been worth 9.5 runs in 68 games). This is especially impressive because Chapman is a third baseman. He is currently worth nearly four runs more than the next best fielding third baseman in baseball, Kyle Seager, who has been worth 6.3 runs above the average third baseman. Overall, Chapman has already proven himself to be a defensive wizard, worth 20.8 runs in just 153 games at the hot corner, and deserves a spot in the argument for baseball’s best fielder.

Moving forward, every number says that Matt Chapman is a star. The only thing to worry about with Chapman is sample size. Chapman’s 2017 scouting report graded his hit tool at an abysmal 35 with a future value of 40, though it acknowledged his raw power at 60. Chapman has not hit for average early on in his career, but if he continues to walk at a 10% rate, hit home runs, and field like a wizard, that will not matter. It’s hard to say whether Chapman will be a superstar as of now: if he stops hitting and lost some of his power, his numbers would be similar to those of Andrelton Simmons before Simmons improved his hitting in 2017. If he continues to hit, Chapman is a four-tool player at worst, only missing a strong average. Chapman is the most up-in-the-air of any of these five players, but based on the early results, he is a franchise fixture for the Oakland Athletics.

Verdict: Fixture

(Featured Image: Erik Drost, Wikimedia Commons)

Categories: Analysis