There are no weak positions heading into 2020, not coming off a record-setting year for offense.

But there are gradients of deep, and from that standpoint, second base comes out a little thin.

It still offers enough impact bats to go around in a 12-team league, but if anyone double dips or if injuries and unexpected role changes intervene, much will be asked of relative newcomers like Gavin Lux, Cavan Biggio and Brandon Lowe. All are capable, but none is a sure thing. And going without a sure thing at any position is a risky approach in an environment that offers so many sure things.

There'd be more wiggle room if Javier Baez and Yoan Moncada weren't losing their second base eligibility. Nick Senzel, Lourdes Gurriel, Daniel Murphy and Nick Solak (who may be DH-only) are among the other second base contributors who will contribute there no longer, at least not at the start of the year.

Top 20 second basemen for 2020
Ketel Marte Arizona Diamondbacks CF
Spoiler alert for those who tuned out in the second half: Ketel Marte's numbers didn't regress as expected but instead got better, lending credence to a breakout few saw coming. An improved launch angle combined with already impressive bat skills allowed the 25-year-old to take off in a way that didn't reveal any red flags, making it hard to doubt him in spite of that nagging feeling he can't possibly do it again.
Jose Altuve Houston Astros 2B
Plagued by leg issues the past two years, Jose Altuve has basically given up on running, which removes him from first-round consideration. But the bat remains as studly as ever, delivering career-best power numbers even though he missed a month with said leg issues. Maybe he overachieved a little in that regard, but the high contact rate and proven track record make the still-only-29-year-old a logical pick here.
Gleyber Torres New York Yankees SS
Those who were surprised by Gleyber Torres' power production as a rookie in 2018 saw him double down on it this year while also whittling down the strikeouts in a meaningful way. The strides he has already made through age 22 foretell greatness, and the star-studded supporting cast clinches his spot among the elites.
Ozzie Albies Atlanta Braves 2B
Ozzie Albies has authored a few fakeouts already in his short career, which might cause him to slip a few spots in a crowded second tier of second basemen, but over the final four months, he put together a believable .300 batting average, seemingly recognizing he didn't have to sell out for power to deliver a respectable home run total. The resulting stat line was well-rounded enough to set him apart in both categories formats (for the steals and batting average) and points formats (for the doubles and strikeouts). 
Whit Merrifield Kansas City Royals 2B
What we saw from Whit Merrifield in 2019 was closer to his worst case than his best case, and it makes him out to be sort of a less powerful version of Albies. Not bad. But he'll need to get back to being a prolific base-stealer to justify an early-round price tag, and between his low success rate on the base paths this year and the fact he'll be 31 next year, it's no foregone conclusion. Those who play in 5x5 leagues are more likely to roll the dice.
DJ LeMahieu New York Yankees 2B
DJ LeMahieu was supposed to falter outside of the welcoming embrace of Coors Field but instead reached new heights with the Yankees. The power especially was foreign to him, but the supporting stats all backed it up. Downgrading him for history's sake is the more prudent course, but in situations where the steals potential of Albies and Merrifield are of little significance to you, LeMahieu has a case to go as high as fourth at this position.
Max Muncy Los Angeles Dodgers 2B
In a crowded second tier of second base-eligible players, Max Muncy's particular flavor may not appeal to all since he's of no real help in batting average. But he's a slugger proven twice over who's now fully entrenched as an everyday player in a deep lineup, elevating his run and RBI totals. And in points leagues, where walks are rewarded like hits, he's an easy call here.
Jeff McNeil New York Mets 2B
Those looking to secure batting average in the early rounds might opt for Jeff McNeil over Muncy if they're totally convinced McNeil's power gains in the second half were legit. They can at least be halfway convinced. The 27-year-old did deliver a big home run total in the minors last year, after all. He's of course more renowned as a contact hitter, with few rivaling his ability to put bat on ball.
Keston Hiura Milwaukee Brewers 2B
Keston Hiura will get more love than this in other places. His bat skills are as advertised, his quality-of-contact measures all pointing to a high ceiling. The question is if there's enough contact, his 30 percent strikeout rate ranking among the highest in baseball, which could be a harbinger of trouble. Given the quality of the players ahead of him, a better-safe-than-sorry approach is warranted.
Jonathan Villar Baltimore Orioles 2B
Maybe the second baseman whose value will be most influenced by format, Jonathan Villar just delivered on a best-case scenario with the Orioles, not only retaining a starting job all year but also fully realizing his power and steals potential. The scarcity of steals across the league might get him drafted as early as Round 3 in a traditional 5x5 league, and maybe it's worth it. Maybe. But it's a big leap for a guy who had a combined .689 OPS the previous two years.
Mike Moustakas Milwaukee Brewers 3B
A nagging hand injury in the second half sidetracked what was shaping up to be a career year for Mike Moustakas, who at the very least has expanded his versatility in his second act with the Brewers. It should make for more suitors this offseason, provided he doesn't simply re-up with Milwaukee. The power has translated whether in that sort of hitter's haven or a pitcher's paradise like Kansas City, so above all, he just needs to land a full-time role.
Eduardo Escobar Arizona Diamondbacks 3B
Though Eduardo Escobar's home run production didn't slow in the second half, it was mostly because he sold out even more for the long ball, elevating his fly-ball rate in a way that was detrimental to his batting average. So if he's going to remain a 35-homer guy, you should recognize it comes with some tradeoffs, which is also true of the man ranked ahead of him.
Gavin Lux Los Angeles Dodgers 2B
The talk of the minors in the second half of 2019, Gavin Lux got eased into a starting role with the Dodgers in September, but going by what little we could deduce from the performance, there's no reason to think he wouldn't have the inside track on the second base job next spring. He was other-worldly at Triple-A, with numbers too good not give him the benefit of the doubt.
Cavan Biggio Toronto Blue Jays 2B
From a walk rate that was nearly the best in baseball to a perfect steals record to a high launch angle that deposited many a ball over the fence, Cavan Biggio offered plenty of reason for optimism in his rookie season. A bloated strikeout rate was a major hindrance, mainly because of its effect on the batting average, but given that it was mostly called strikes bringing him down, a refined approach could work wonders.
Ryan McMahon Colorado Rockies 2B
Ryan McMahon's fine numbers at home at least assure him a lineup spot next year, and seeing as he'll be only 25, there's still plenty of hope for him to improve. The increased power production in the second half, though, was misleading in that it came with an even higher ground-ball rate, and between that and the strikeouts, Coors Field is basically carrying McMahon at this stage of his career.
Brandon Lowe Tampa Bay Rays 2B
Brandon Lowe seemed to be making a name for himself as the Rays' primary second baseman before shin and quad injuries wrecked his season, but he, like so many of the other up-and-comers at this position, has a glaring strikeout problem that likely would have come home to roost if he had gotten more reps. He hits the ball hard and was a much more disciplined hitter in the minors, leaving reason for hope, but the Rays are crawling with infielders and may not be fully committed to him.
Tommy La Stella Los Angeles Angels 2B
The surprise breakout of the first half broke his leg in early July and only made it back for the final weekend of the season, which raises serious doubts about Tommy La Stella's 2020 role given that he's a 31-year-old journeyman and not some long-awaited prospect. He's an unusually good contact hitter, though, whose power breakthrough was at least partially supported an improved launch angle. And it's not like anyone stepped up in his absence.
Robinson Cano New York Mets 2B
It was easy to dismiss Robinson Cano during a miserable first half -- he'll be turning 37 this offseason, after all -- but his strong return from an August IL stint demanded a closer look at the numbers. What they show is a player whose skills remain mostly intact -- one who may have fallen victim to luck rather than age. It's kind of a long shot, but there's hope Cano is a quality contributor still.
Luis Arraez Minnesota Twins 2B
Maybe Luis Arraez can pull a La Stella someday and magically start hitting balls over the fence -- he's only 22, after all -- but for now, his game is all contact. And he's well suited for it with an elite line-drive rate and opposite-field approach. Another .350 batting average is too much to hope for, but seeing as he also walks a ton, a more permanent move to the top of the Twins lineup could make him a Fantasy regular at this position.
Kevin Newman Pittsburgh Pirates SS
Kevin Newman is sort of a less extreme version of Arraez, but without as much hope for improvement given that he's already 26. The contact skills are good enough to make a .300 hitter out of him, and he's not a complete zero in home runs and stolen bases. It's not a whole-is-greater-than-the-sum-of-the-parts situation, but it's enough to make him a handy fallback pick.