If there's a foolproof position in 2020, it's third base. You'd have to try to mess it up.

The depth is most evident when comparing where the multi-eligible players rank at other positions, which I've made a point to note when applicable. 

That's not to say there aren't different levels of impact therein — tiers, if you will — and of course some (maybe even most) of the dual-eligible players will get drafted to play elsewhere. But there comes a point in the rankings — whether it's after the top seven or the top 10 — where everyone seems too low. They can't all be No. 11.

And the exclusions, oy. Hunter Dozier, Gio Urshela and Yandy Diaz are just a few of the notable names I had to leave out. Oh, but did I forget about Miguel Andujar? Nope, he'll be DH-only to begin next year, though you have to imagine he'll be joining this mix soon enough.

Top 20 third basemen for 2020
1
Nolan Arenado Colorado Rockies 3B
If we're talking more of a points-league context or any format that rewards walks or on-base percentage, it might be time to drop Nolan Arenado behind Alex Bregman and Anthony Rendon, who both have him beat in that regard. But in traditional 5x5 categories scoring, he can do no wrong playing half his games at Coors Field, remaining a perennial triple crown threat and four-category stud.
2
Alex Bregman Houston Astros 3B
Now proven as a power hitter twice over, Bregman only lags behind Arenado in batting average, but given that he actually strikes out less, it won't take much for him to catch up there either. Hitters who walk more than they strike out are rare in today's game, and the gap between the two numbers seems to widen every year for Bregman, which makes him a no-doubt first-rounder in points leagues.
3
Anthony Rendon Washington Nationals 3B
For a second straight year, Anthony Rendon was the top third baseman in terms of Head-to-Head points per game, but the reason it may come as a surprise to you is because he always seems to miss a chunk of games. Of course, the gap was so wide this year that those health concerns alone aren't reason enough to downgrade him, but the power increase at age 29 isn't something you can just assume he'll repeat.
4
Rafael Devers Boston Red Sox 3B
Though 2019 was obviously a massive breakout for the 22-year-old, who could continue to get better from here, Rafael Devers' elite standing is in question after a bumpy finish. If the composition of the Red Sox roster changes a great deal this offseason, which is certainly possible with a regime change, it could chip away at his massive RBI and run totals, and I wouldn't say he's a surefire .300 hitter yet. But overall, you have to like the direction he's headed.
5
Jose Ramirez Cleveland Indians 3B
Those who worship at the altar of the stolen base will most likely draft Jose Ramirez ahead of Devers, and there's a case to be made for going that route in a points league as well. Ramirez has incredible contact skills and was the consensus third overall pick heading into this year. But even though he appeared to return to that form in July, I can't help but downgrade him for the near year-long stretch in which he hit about .200, especially since it ended just as unpredictably as it began.
6
Kris Bryant Chicago Cubs 3B
Kris Bryant has built up enough legacy points to retain this high ranking, but he's on thin ice at a position where about a dozen bats are angling to overtake him. It's not that he's bad now, but he's been playing banged up the past couple years and has struggled to regain the power production that seemed so natural at the start of his career, propelling him to NL MVP in Year 2. Particularly in formats that don't reward his on-base skills, he may not be anything special in this environment.
7
Eugenio Suarez Cincinnati Reds 3B
Eugenio Suarez was looking like a mild disappointment for the first half of the season, but a home run explosion in the second half had him closing in on 50, which was certainly enough to stand out even in an increasingly plentiful category. The rising strikeout rate is a little concerning, but he has now demonstrated a variety of ways he can go right.
8
DJ LeMahieu New York Yankees 2B
Ranked sixth at both first and second base, DJ LeMahieu is a tougher sell here, but the multi-eligibility is part of what you're paying for. Clearly, his 2019 production more than justifies this ranking, and because the underlying numbers all back it up, the biggest knock on LeMahieu is that nobody saw it coming. It's a relevant argument but, to me, not the most compelling one, and his spot at the top of a loaded Yankees lineup should at least give him a high floor.
9
Max Muncy Los Angeles Dodgers 2B
Though he mostly validated his 2018 breakthrough as an elite power source who walks a bunch, Max Muncy's sluggish second half pulled down his numbers enough to make him a tough sell this high at this position. But I rank him seventh at both first and second base, which is more likely what he'll be drafted to fill, and it elevates his stock here. Maybe you could drop him a couple spots in leagues where his walks don't matter.
10
Jeff McNeil New York Mets 2B
Ranked eighth at second base, the same caveat applies here as there: Drafting Jeff McNeil this high only makes sense if you buy his second half power surge. Personally, I was anticipating it after seeing what he did in the minors last year, but it's true he spent the first 365 days of his big-league career carving out a niche as more of a Luis Arraez type. He has those contact skills to fall back on, at least.
11
Yoan Moncada Chicago White Sox 3B
Those who prioritize upside will see fit to elevate Yoan Moncada, who has improved by leaps and bounds this year. His batted-ball profile is an impressive one, but not so impressive that you can expect him to repeat a .400 BABIP. So while his strikeout rate has improved enough to make him good, it'll need to improve some more to make him elite. A home run increase would also do the trick, and it's certainly a possibility.
12
Matt Chapman Oakland Athletics 3B
In theory, the skills are in place for Matt Chapman to ascend to Fantasy glory. He strikes out and walks at respectable rates, hits the ball hard and elevates well. But the line-drive rate is so low that the BABIP -- and, with it, the batting average -- has suffered. So the ascension from good to great remains mostly theoretical for now, but the will-be 27-year-old has nonetheless made enough strides over the past couple years that he's pretty useful just as he is.
13
Manny Machado San Diego Padres 3B
Judging from way-too-early mock draft results among industry types, Manny Machado may well get a pass for a disappointing first year in San Diego. He's only 27, after all, and has been in the first-round discussion for half a decade. Look, I'm giving him some benefit of the doubt by ranking him this high, but when you break down the splits year by year, it's looking more and more like he's especially vulnerable to venue. And Petco Park ain't no Camden Yards.
14
Vladimir Guerrero Toronto Blue Jays 3B
Some will insist this ranking is too low given that Vladimir Guerrero went even higher this spring, back when he didn't have a job yet. But while the future is still bright for the 20-year-old and the pedigree suggests improvement is almost a given, the fact is his transition to the majors could have gone better. He has some work to do, namely with regard to launch angle, and while it may happen at the snap of a finger, there's no need to assume such at this position.
15
Josh Donaldson Atlanta Braves 3B
Good news, everyone! Josh Donaldson is back. But if he was formerly a perennial MVP candidate, why is he now barely a top-15 third baseman? Well, someone has to rank this low, and the harsh reality is he's a soon-to-be 34-year-old whose career was recently in jeopardy because of injury concerns. We also don't know where he'll be landing this offseason. Theoretically, his upside is similar to Muncy, which shows how narrow the gap is between nine in 15.
16
Miguel Sano Minnesota Twins 3B
Nobody strikes out more than Miguel Sano, but at least according to FanGraphs, nobody hits the ball harder either. And that's a profile that can work in the modern game, as Aaron Judge and Joey Gallo have demonstrated. It doesn't take a statistician to project out Sano's numbers and see he has 50-homer potential if he can stay on the field, and even in points leagues that penalize for strikeouts, it would probably make him top-10 at the position.
17
Mike Moustakas Milwaukee Brewers 3B
Ranked 11th at second base -- yeah, the differences in positional depth are really beginning to show now -- Mike Moustakas has proven he can hit for power whether playing in Kansas City or Milwaukee, so where he signs this offseason won't be of great significance as long as it's to fill a full-time role. His limited on-base ability makes him kind of a boring choice for this position, though.
18
Eduardo Escobar Arizona Diamondbacks 3B
Ranked 12th at second base because he's the last of the surefire contributors at that position, Eduardo Escobar isn't as impressive at this one. Yeah, it's a big home run total he delivered, but he had to sell out so hard for power that there's not much else to fall back on. In fact, the batting average is probably a little higher than it should be. The overall package isn't so different from Moustakas, but it's less proven.
19
Yuli Gurriel Houston Astros 1B
Ranked 14th at first base, Yuli Gurriel will be a gamble in 2020 not only because he's 35 but also because he never profiled as a power hitter until about July of this year. He elevated better and hit the ball harder, and it's not like his home run-to-fly ball rate was excessive. Can't rule out it's legit. But if that was the presumption, particularly while factoring in his potential for batting average, he'd be top 10 here.
20
Justin Turner Los Angeles Dodgers 3B
Justin Turner has long had trouble staying on the field, and those issues will become even more pronounced when he's on the wrong side of 35 next year. In fact, much of the time he missed this year was because of routine days off, and the Dodgers are never hurting for depth. The bat skills are as impressive as ever, and it's fair to assume he'll challenge for a .300 batting average and .900 OPS again. But it's a lot of trouble for those numbers, looking at the alternatives.