Who's going to bust out as a star this year, and who's simply going to bust? Before the start of the regular season, Cliff Corcoran and Jay Jaffe are picking 10 players (five from each league) who appear to be headed for breakout seasons and 10 players likely to be disappointments. Be sure to bookmark these articles so you can tell them how wrong they were in September.

As with my previous choices for the top busts in the American League, my attempts to identify the biggest busts in the National League account for players’ overall performances—defense as well as offense. Such an exercise can devolve into shooting fish in a barrel, but this is a quintet of players who do have some track record of success in the majors, are being counted on to occupy significant jobs, are not projected to miss significant time due to injuries (though a couple are coming back from injuries at the moment) and were not below replacement level last year.

What complicates this exercise at the moment is that so many NL teams are in rebuilding phases, and picking on fringe players from the likes of the Phillies, Braves, Rockies, Reds and Brewers is far too easy, though as you can see below, even those teams have established players who aren't exempt from consideration. Thus the actual level of quality may be a bit higher here relative to the AL. The players are listed alphabetically.

Asdrubal Cabrera, SS, Mets

Can a player be both an upgrade over his predecessor(s) and a bust? That's my bet here. Last year's Wilmer Flores/Ruben Tejada tandem was a combined 25 runs below average at the position, according to Defensive Runs Saved, and the duo's offensive contributions in that capacity (.256/.307/.370) were nothing to write home about either. In December, the Mets signed the 30-year-old Cabrera to a two-year, $18.5 million deal, a move that offered a shot at improvement but hardly a guarantee of one.

Who will be National League's breakout players in 2016?

Since making the AL All-Star team in both 2011 and '12, Cabrera has ridden the down escalator in passing from Cleveland to Washington to Tampa Bay and now New York. During that time, he's been worth a combined 3.7 Wins Above Replacement (baseball-reference.com version) with a whopping -30 DRS at shortstop (I'm ignoring his -10 DRS in 48 games at second base for the Nationals in 2014), and both his bat and glove have declined. In 2015 with Tampa Bay, the switch-hitting shortstop batted .265/.315/.430 with 15 homers and a 105 OPS+, an 11% improvement over the previous two seasons. He was seven runs below average via DRS, however, and other systems such as Ultimate Zone rating (-6) and Runs Effectively Defended (an AL-worst -9)—the latter of which is used within the sabermetric component of the Gold Glove calculations—don't like him either. Via bWAR, which uses DRS, his 1.7 mark was his third below-average showing in a row.

Playing in a division with a pair of rebuilding teams, Cabrera's bat may get a lift against subpar pitching. But his shoddy glove work will drive Mets fans nuts.

Howie Kendrick, 2B, Dodgers

Kendrick did not have a great year in switching from Angels red to Dodgers blue. He hit .295/.336/.409 for a 107 OPS+, and while that was in line with his overall career mark (108), it represented a 10-point drop from 2013–14. What's more, he missed five weeks due to a left hamstring strain, the second time in three years he's missed substantial time with a leg injury. That's an ominous sign for a middle infielder heading into his age-32 season. Meanwhile, his defense slipped substantially according to multiple metrics; via DRS, he crashed from +7 in 2014 to -12 last year, and via UZR, he swung from +7 to -5. Based on DRS, his bWAR plummeted from 5.3 to 1.1, and thanks to his plunging UZR, his FanGraphs WAR slipped from 4.7 to 2.1.

Picking five breakout candidates for 2016 in the American League

Either way, delivering less than half the value of the previous season isn’t a good trend, and while the qualifying offer Kendrick received no doubt limited his market as he hit free agency, it's telling that no other team was particularly keen to offer him a multiyear deal. He wound up returning to the Dodgers via a two-year, $20 million deal that includes $5 million per year deferred without interest. That may make him a bargain, relatively speaking, but it does not portend a return to the 4.0 WAR that he averaged from 2011 to '14. Having also retained Chase Utley and Kiké Hernandez and traded for Micah Johnson, the Dodgers aren't without alternatives at the keystone, and it's not hard to imagine that further slippage from Kendrick could significantly cut into his playing time.

Yadier Molina, C, Cardinals

Always an outstanding defender—an eight-time Gold Glove winner and four-time Platinum Glove winner—Molina's offense may be in an irreversible decline from the 130 OPS+ he posted from 2011 to '13. In 2014, when he missed seven weeks due to in-season surgery for a torn ligament in his right thumb, he slipped to a 102 OPS+. Last year, in his age-32 season, things got even worse, as he hit just .270/.310/.350 for an 80 OPS+, his lowest mark since 2006. Worse, he sprained his left thumb in late September and needed not one but two surgeries on it—the first in October in an attempt to repair the torn ligament, the second in mid-December when a full-blown reconstruction (involving a tendon graft, typically) was needed after the repair proved insufficient.

Last week, Molina made his spring training debut despite having not been cleared to take batting practice yet; he was lifted for a pinch-hitter when his spot in the order came up. Since then, he's progressed from BP to swings in games, but thus far he's 0 for 3 with three strikeouts and a sacrifice bunt. While the fact that he’s hitting in game situations would appear to increase the likelihood that he'll be in the Opening Day lineup, I'm simply not optimistic about the return of his offense due to the late start and the fact that he struggled so mightily in 2015 despite being even further removed from his first surgery than he will have been from his most recent one.

Who are American League's biggest bust candidates for 2016?

Via Brooks Baseball, Molina’s whiffs-per-swing rates against fastballs and offspeed stuff both edged upward last year—the former from 12.9% to 16.2—and his batting average and slugging percentage against two- and four-seamers sank from .337 and .513 during the 2011–13 span to .279 and .337, respectively, over the last two seasons. That all suggests some combination of slowing bat speed and the lingering effects of his injuries. Though Molina's defense and handling of the pitching staff will be more than enough to justify his presence in the lineup and guide the Cardinals to another postseason appearance, his days as an offensive threat are probably behind him.

Ben Revere, CF, Nationals

Having let a very banged-up Denard Span depart via free agency, the Nationals brought in Span-lite in Revere, a 28-year-old speedster who has topped a .300 batting average in each of the past three seasons. Thanks to a strong two-month stretch after being acquired by the Blue Jays—one in which he posted a 104 OPS+, 16 points above his career mark—Revere hit .306/.342/.377 in 634 plate appearances last year, finishing with a career-best 98 OPS+ and 2.6 WAR.

Color me skeptical that he can sustain even that level. Revere's 5.0% walk rate is dreadful for a player whose best hope for positive contributions lies in getting on base and stealing (he swiped 31 in 38 attempts last year), and whatever power he offers has more to do with legging out doubles and triples than hitting the ball over the fence; he has two homers apiece in each of the past two seasons. As for his defense in center, Revere's -26 DRS over the past four seasons admittedly tells a different story than his -7 UZR, but all told, the package makes more sense as a fourth outfielder, as his defensive numbers are better at the corners.

The Nationals do have an alternative to start in center in Michael Taylor, who endured a rocky season last year, but given Jayson Werth's penchant for injuries, it's quite likely both Taylor and Revere wind up in the same lineup. Unless Revere can push his on-base percentage well above .350, he's just not an asset outside of fantasy baseball, where his steals are gold.

James Shields, SP, Padres

Signed to a four-year, $75 million deal by the Padres in February 2015, Shields was his usual durable self, topping 200 innings for the ninth straight season and reaching 33 starts for his eighth straight year, but his performance took a dip. He led the NL with 33 homers allowed (1.5 per nine) and walked a career-worst 3.6 per nine despite striking out a career-best 9.6 per nine, finishing with a 3.91 ERA (93 ERA+) and a career-worst 4.45 FIP.

Normally, something like Shields' inflated 17.6% rate of home runs per fly ball—six points above his career mark and almost double that of his two years in Kansas City—could be waved off as a fluke, particularly in a pitcher-friendly park such as Petco. But the venue doesn't play as it once did due to configuration changes; in fact, the Padres' staff as a whole had an NL-high 14.8% HR/FB rate at home last year, so expecting Shields to bounce all the way back could be a stretch. What's more, he lost around 1.5 mph on his fastball relative to 2014, which has to be a concern for a 34-year-old with more than 2,100 major league innings on his odometer.

Shields has bounced back from subpar seasons before, following a 5.18 ERA in 2010 with a 2.82 mark in '11, and perhaps he'll make adjustments in his second lap around the league. But I don't see him getting all the way back to being the Big Game James of yore.