If you can believe it, Opening Day is only four weeks away, and we're previewing each division every Wednesday. Baseball is an individual sport masquerading as a team sport, so we'll be previewing each division by counting down the 20 most pivotal players in the division. These aren't necessarily the best players. They're just the ones whose 2018 performance will be most vital to their teams' success this season, and in seasons moving forward. To keep it fair, we can only pick four players from each team.

Today: The National League West. Tell me what you think not just about this list, but also whom I should not miss when I do the American League Central next week, at [email protected].

Previously: NL Central | AL East

20. Ryan McMahon , Colorado Rockies

McMahon has shown considerable talent in the Minors -- he hit .374 in 70 games for Triple-A Albuquerque last year -- and the Rockies have rewarded him by giving him every chance to win the first-base job. But in a world where Logan Morrison is only getting $6.5 million a year, is entirely trusting the rookie at an easily upgradable position the right call?

19. Manuel Margot , San Diego Padres

Margot's first full season in the Majors gave us a rough sketch of the player he is, and who he might become. Present: Plays a great center field, can run like crazy, brings energy and youth to the top of the lineup and has a little more power than we may have thought. Future: Needs to strike out less, walk a lot more and generally just get that on-base percentage higher. Also, can we just all call him Manny now?

18. Brandon Crawford , San Francisco Giants

The 2017 season was a nightmare for Crawford, losing a close family member in April, suffering from minor nagging injuries all year and ultimately putting up the worst numbers of his career. He was nearly a six-win player in 2016, and if he can return to something close to that form, the Giants, for all their offseason acquisitions, will find one of their biggest improvements from within.

17. Archie Bradley , Arizona Diamondbacks

Another reminder that yesterday's failed starters are often tomorrow's dominant closers, Bradley thrived in relief in 2017, striking out more than a batter per inning and exhibiting pinpoint control that eluded him previously in his career. The D-backs are still debating whether or not he'll be the closer, but if he's not, it's because they want to deploy him in the highest-leverage position possible. Bradley is key to everything Arizona's bullpen does.

16. Fernando Tatis Jr. , San Diego Padres

All right, so Tatis is probably not going to get called up until September, if even then. But at 19, he's already the most exciting prospect the Padres have had in years, and with only Freddy Galvis (whose contract is up at the end of the year and thus has no real reason for San Diego to stick with him) ahead of him, the club will have to be tempted if he's raking in the Minors. This franchise is all about the future, and Tatis is the face of that future. Though if he doesn't hit two grand slams in an inning, I won't be impressed. (Does Chan Ho Park have any pitching sons?)

15. Joc Pederson , Los Angeles Dodgers

The advantage of being the Dodgers is when you have a young hitter like Pederson -- who looked like a budding superstar at age 23 -- struggle, you can give him time to figure it out and still have plenty of options if he doesn't. The step backward last season led to many Dodgers fans losing patience with him, but he's still just 25 and coming off an excellent postseason. Pederson may need to produce now, though, or he may find himself on the bench … or on another team.

14. Tyler Anderson , Colorado Rockies

The dirty secret about the Rockies is that their team strength is pitching, not their lineup. But to repeat its 2017 success, Colorado will need Anderson, who missed much of last year with a left knee injury but was excellent when he returned in September, to become a rotation mainstay. Many in Denver think he's due for a breakout season, but the metrics are more skeptical.

13. A.J. Pollock, Arizona Diamondbacks

Pollock was one of the 10 most valuable players in baseball in 2015, and it's been all about staying on the field since then. He missed almost all of '16 with a right elbow injury -- derailing the D-backs' season right along with him -- and his return in '17 was hampered by a groin injury. Pollock is still a fantastic center fielder with power and speed, but he's also 30 years old now. Can he be that '15 player again?

12. William Myers , San Diego Padres

Myers has benefited in recent years of being the biggest fish in the small San Diego pond, looking like a brighter star than he is because there was nobody else around. Now that Eric Hosmer is in town, he has some help, but he'll have to move to the outfield to make room. Myers still doesn't quite get on base enough and is a larger factor in fantasy baseball than in reality, but he's only 27; maybe there's more growth to be had.

11. Cody Bellinger , Los Angeles Dodgers

The power was downright staggering at times -- Bellinger is one of those players who makes hitting homers look easy -- but it sure was brutal to watch him in the postseason. That ugly October, including those 17 World Series strikeouts in 29 at-bats, has many predicting a sophomore slump. But even a slump probably ends with 35-plus homers. He's going to hit 50 soon. If it's this year, the Dodgers might not lose a game.

Halftime mascot break! NL West mascots, ranked.

1. Lou Seal

All love to the Crazy Crab, but everybody loves seals, particularly ones that wear sunglasses.

2. Swinging Friar

You can keep your Chicken. I'll stand with the Friar, who has always struck me as what your biology teacher would look like if he were a cartoon. He could probably use some help with the hair, though.

3. Dinger

You're not going to count me among the Dinger haters. Someone probably needs to get him a bigger jersey though.

4. Baxter the Bobcat

Baxter's got spirit, but he's still mostly indistinguishable from a mascot for a middle-tier college basketball team. He has his utility, though: A snake mascot would probably be too scary.

5. Unknown Dodgers mascot

This scary thing doesn't count, and, alas, neither does Rally Bear.

10. Evan Longoria , San Francisco Giants

It's going to take half the season just to get used to Longoria in that uniform.

9. Andrew McCutchen , San Francisco Giants

Oh, McCutchen even more so.

8. Ian Desmond , Colorado Rockies

Many questioned the Rockies' signing of Desmond before last season, but 2017 went even worse than the most grizzled skeptic could have anticipated, with a broken left hand in Spring Training, a strained right calf later in the year and all sorts of positional confusion. It ended up a lost year, but he's still a line-drive hitter with speed who now doesn't have to pretend he's a first baseman. Colorado had one of its best seasons without Desmond contributing much last year; if he can at least approach what they thought they were buying, this lineup gets some much-needed depth.

7. Robbie Ray, Arizona Diamondbacks

How do you improve on a season in which you shaved two runs off your ERA and posted the highest strikeouts per nine innings in the NL? Ray maybe walked a few too many guys in 2017, and he sometimes had a difficult time going deep into starts. If he can add more innings pitched and chop off a few walks, you're looking at an NL Cy Young Award contender. Ray says last season was "the floor." If so, look out.

6. Eric Hosmer, San Diego Padres

The contract was a lot, but San Diego has to spend that money somewhere, so why not spend it on a steady, if unspectacular, producer who you can put in the lineup every day for the next half-decade and feel positive about it? You'd like Hosmer to join the "launch angle revolution," but even if he doesn't, he's still the best hitter on a team that, frankly, could use a few more like him. Plus: Face of the franchise! (Until Tatis gets here.)

5. Yasiel Puig , Los Angeles Dodgers

All right, the agent thing was pretty strange, and definitely raised all those eyebrows that are constantly raising whenever Puig's name comes up. But from 10,000 feet up, it sure looks like the Dodgers have their budding star back. Puig shook off two subpar seasons to put up career highs in homers, RBIs and stolen bases, and while the average probably isn't going to approach .300 again, that arm in right field more than makes up for that. The Dodgers stuck with Puig through all the turmoil, and they have been rewarded. Now, as long as all that turmoil is over … And it is, right? Right?

4. Wade Davis , Colorado Rockies

Colorado's bullpen splurge stunned the game this offseason, spending more than $100 million on three guys to theoretically set up a dominant end-of-game strategy. It's not a terrible way of doing business in 2018, but Davis might have been the riskiest of the investments. Sure, he only blew one save last year for the Cubs, but his velocity was down and his walk rate way up. The Rockies think they're getting a shutdown closer. Their season may depend on it.

3. Paul Goldschmidt , Arizona Diamondbacks

We're never going to fully appreciate Goldschmidt. He put together another jaw-dropping season in 2017, reaching his career high in homers and remaining one of the most consistent players in the sport. The advantage Goldschmidt had last year that he won't this year is J.D. Martinez next to him in the lineup. The Diamondbacks have gotten MVP production from a guy who has never made more than $10 million in a season; that allows for a rather wide margin of error elsewhere. But he went six seasons in between playoff appearances. Without Martinez and entering his 30s, how long will Goldschmidt have to wait for the next one?

2. Madison Bumgarner , San Francisco Giants

Bumgarner avoided the injury bug that takes down most pitchers for his entire career until, ultimately, the dirt bike got him. He wasn't quite himself when he returned, though, to be fair, the Giants' season was long lost by that point. For all the postseason love, Bumgarner, if you can believe this, has never actually finished higher than fourth in the NL Cy Young Award voting. He is still somehow only 28 years old -- he's younger than Tommy Pham! -- and has two years left on the deal he signed in 2012 before he can finally hit the free-agent market. Now would be the time to get one of those Cy Young Awards.

1. Clayton Kershaw , Los Angeles Dodgers

Of course, this guy might have something to say about that, and he might have a free agency coming up of his own, were he to opt out of his contract at the end of the year. (Fun fact: Kershaw has already made almost $100 million more than Bumgarner in his career.) Kershaw remains the best pitcher in baseball by a wide margin, but he's gotta stay on the mound; if he had stayed healthy the last two seasons, he would probably have five NL Cy Young Awards by now. If he can reach 200 innings, which he hasn't done since 2015, he'll win another NL Cy Young Award, maybe an NL MVP Award and make all the money next offseason. And he might just get the Dodgers back to the World Series. Kershaw turns 30 in three weeks. With health, we're looking at peak Kershaw. Yikes.

We finish this preview, as we will with all of them, with predictions. I apologize in advance because these predictions are guaranteed to be correct and thus I'm a little worried I'm spoiling the season for you.

Los Angeles Dodgers: 102-60

Arizona Diamondbacks: 86-76

San Francisco Giants: 83-79

Colorado Rockies: 78-84

San Diego Padres: 71-91