Only one World Series favorite entering the season actually won the World Series in the decade we just completed. Wait, let's put that another way: A team that was one of the top five favorites entering the season won the World Series only once over the past decade.

The 2019 Washington Nationals didn't necessarily feel like a surprise champ, given the star-laden nature of the team and their many playoff appearances throughout the decade, but they were coming off a mediocre 82-80 season, had lost Bryce Harper in free agency and entered the season just ninth among World Series favorites, according to the betting odds.

Here are the final preseason odds for the decade's champions, via sportsoddshistory.com, along with where that team's odds ranked among the 30 franchises, the team's win total from the previous season and how much it improved during its championship year:

2019 Nationals: +1600, ninth (82, +11)
2018 Red Sox: +1150, seventh (93, +15)
2017 Astros: +1175, sixth (84, +17)
2016 Cubs: +660, first (97, +6)
2015 Royals: +3300, 18th (89, +6)
2014 Giants: +2500, 13th (76, +12)
2013 Red Sox: +2800, 14th (69, +28)
2012 Giants: +2000, seventh (86, +8)
2011 Cardinals: +2500, 10th (86, +4)
2010 Giants: +2500, 11th (88, +4)

Only two of the 10 championship teams won 90 games the season before. This doesn't mean the Yankees, Dodgers or Astros -- the current top three favorites -- won't win the World Series this year. It doesn't even suggest the postseason is a complete crapshoot; after all, the 2016 Cubs, 2017 Astros and 2018 Red Sox each won more than 100 games (and the 2019 Astros might have been a fourth straight 100-win champ if Howie Kendrick hadn't hit that improbable home run off Will Harris in Game 7 of the World Series).

It does suggest, however, that predicting the World Series winner in March is not easy. As powerful as the Dodgers, Yankees or Astros look right now, over the past 10 years, only the 2016 Cubs looked like a superteam heading into the season and ended up raising the piece of metal in October.

With that in mind, we ask what team is this year's Nationals? What team might be this year's surprise champ?

First off, let's eliminate two groups of teams:

Last year's 90-win teams: Astros, Dodgers, Yankees, Twins, Braves, A's, Rays, Nationals, Indians, Cardinals. Of those 10 teams, the Indians currently have the longest betting odds at +3000, ranking 18th. (Personally, I'll take the Rays at +2500.)

This year's bad teams: Two of the above World Series winners had losing seasons the previous year, and the 2012 Red Sox won just 69 games. Going back even earlier, eight other teams in the division era (since 1969) won the World Series coming off a losing season: 2003 Marlins (79 wins), 2002 Angels (75), 1997 Marlins (80), 1991 Twins (74), 1990 Reds (75), 1988 Dodgers (73), 1987 Twins (71), 1969 Mets (73).

Nonetheless, the vast majority of 71- or 73-win teams do not reach the playoffs the next season, let alone win it all. For 2020, I don't see a road to the World Series for the following teams, which also are the seven teams with the longest betting odds: Tigers, Orioles, Marlins, Royals, Mariners, Giants and Pirates.

Here is a look at some of the elements that have boosted the recent championship teams and how this year's potential surprise contenders fit in.

Keep the rotation healthy

The first step to winning the World Series is making the postseason. The Nationals tied for the eighth-most wins in the majors last season, but that got them in the tournament. To make the postseason, an overlooked precept is simply to have your starting pitchers stay healthy. One thing I like to look at is how many starts a team got from its four most-used starters. If you get to 120, that means those four averaged 30 starts apiece. That's the goal.

The Nationals got 123 starts in 2019 from Stephen Strasburg, Patrick Corbin, Anibal Sanchez and Max Scherzer, with only Scherzer missing a chunk of time. They never really did solve the No. 5 spot in the rotation, but that's common for most teams. Keep your top four healthy and you have a good foundation for a successful season.

Here's how the past 10 champs fared in this area:

2019 Nationals: 123
2018 Red Sox: 113
2017 Astros: 98
2016 Cubs: 123
2015 Royals: 109
2014 Giants: 122
2013 Red Sox: 118
2012 Giants: 128
2011 Cardinals: 129
2010 Giants: 132

Only the 2017 Astros had a major scramble with their rotation as Mike Fiers led the team with 28 starts and seven pitchers made at least 12 starts. Of course, the Astros also made a key August addition to the rotation in Justin Verlander.

Teams that fit here:

1. New York Mets. The Mets obviously have the makings of an outstanding rotation with two-time reigning Cy Young winner Jacob deGrom, Noah Syndergaard, Marcus Stroman, Steven Matz and Rick Porcello, with Michael Wacha in reserve. The first five guys all made at least 30 starts last season, and FanGraphs projects the Mets with the second-best rotation in the majors (behind the Nationals). The Mets won 86 games last season, so it doesn't take much improvement to get them into playoff range.

2. Arizona Diamondbacks. Coming off an 85-win season, the rotation figures to be the strength of the team. Madison Bumgarner joins Robbie Ray, Zac Gallen, Luke Weaver, Mike Leake and Merrill Kelly. Weaver missed time last season, but the others were all healthy. FanGraphs is only lukewarm on this group, ranking it 21st, but that seems low given that all except Kelly project to 2.0 WAR or higher (meaning an average major league starter). Maybe the ceiling is somewhat limited -- although I love Gallen, and Ray's stuff remains tantalizing -- but this rotation has a very high floor.

3. Texas Rangers. The Rangers went 78-84 in 2019 even though three-fifths of their rotation was a disaster. Mike Minor and Lance Lynn were terrific, but Ariel Jurado was third on the team with 18 starts -- and he had a 5.81 ERA. Enter Corey Kluber, Kyle Gibson and Jordan Lyles. If Kluber bounces back from his injury-shortened season and Minor and Lynn pitch well again, that's a dynamic top three. Then all they would need is for Gibson and Lyles to remain healthy. I have concerns about Texas' offense, and the AL West is tough at the top with Houston and Oakland, but the Rangers' rotation could anchor a surprise team.

Teams that don't fit here:

1. Los Angeles Angels. The Angels have perhaps the worst track record in recent years in keeping a rotation together. The Angels didn't have a single pitcher make 20 starts in 2019 and have had just 10 pitchers make 20 starts over the past five seasons -- and that's 10 different pitchers. The Angels brought in Julio Teheran and Dylan Bundy to hopefully add 60 starts, but Griffin Canning is already sidelined with a sore elbow. Canning said his recent MRI showed "normal wear and tear," but if he starts the season on the injured list, it will mark his third IL stint for elbow discomfort since August.

2. Boston Red Sox. Boston's top three starters are Chris Sale, who has missed time each of the past two seasons; Nathan Eovaldi, who made just 12 starts last year; and Eduardo Rodriguez, who made 34 starts and pitched 203⅓ innings last season but cleared 24 starts for the first time since his rookie season in 2015. After that, you get to Martin Perez and ... Ryan Weber? This team needs 90 starts from Sale, Eovaldi and Rodriguez and has to hope somebody steps up as the No. 4 guy.

Have an MVP candidate ... or two

The Nationals lost Harper for 2019, but Anthony Rendon had his best season, hitting .312/.412/.598, leading the majors with 126 RBIs and finishing third in NL MVP voting. Juan Soto finished ninth in the MVP voting. All 10 of our champs had a top-10 MVP finisher -- including four guys who won:

2019 Nationals: Rendon, 6.3 WAR (third in voting)
2018 Red Sox: Mookie Betts, 10.9 (first)
2017 Astros: Jose Altuve, 8.1 (first)
2016 Cubs: Kris Bryant, 7.4 (first)
2015 Royals: Lorenzo Cain, 7.2 (third)
2014 Giants: Buster Posey, 5.4 (sixth)
2013 Red Sox: Dustin Pedroia, 6.3 (seventh)
2012 Giants: Buster Posey, 7.6 (first)
2011 Cardinals: Albert Pujols, 5.3 (fifth)
2010 Giants: Aubrey Huff, 5.7 (seventh)

Teams that fit here:

1. Los Angeles Angels. With Mike Trout and now Rendon, the Angels have perhaps the best 1-2 combo in the game. Since his rookie season of 2012, Trout has had just three other 5-WAR position players as teammates: Andrelton Simmons, who did it twice but primarily because of his glove, Torii Hunter way back in 2012 and Howie Kendrick in 2014. Trout has never had a teammate with a .900 OPS. In large part because of Trout and Rendon, FanGraphs ranks the Angels fourth in projected position-player WAR.

2. San Diego Padres. If you want to dream on the Padres, dream on the 1-2 dazzling duo of Fernando Tatis Jr. and Manny Machado. Tatis was worth 4.2 WAR in 84 games in his exhilarating rookie season. That's 7.5 WAR over 150 games. Machado had an up-and-down first season with the Padres and was worth only 3.1 WAR, but from 2015 to 2018, he averaged 5.8 WAR per season.

3. Colorado Rockies. Nolan Arenado is an annual MVP candidate, but Trevor Story led Arenado in Baseball-Reference WAR in 2019 (6.4 to 5.7) and matched him in 2018 (5.6). Story finished eighth and 12th in the MVP voting the past two seasons.

Teams that don't fit here:

1. Cincinnati Reds. The rotation has a chance to be very good, which is why the Reds are at +2,000, the same as the Rays and Angels and better than the Brewers and Twins. They added Mike Moustakas and Nick Castellanos, but those aren't MVP-type players, and neither is Joey Votto anymore. The highest projected WAR for a Reds position player is Eugenio Suarez at 3.3, and he just started rehab after shoulder surgery. Suarez did hit 49 home runs last year and had 4.5 WAR, but that got him to just 15th in the MVP voting.

2. Toronto Blue Jays. Bo Bichette and Vladimir Guerrero Jr. are certainly impressive young talents, but MVP-level talents as sophomores? That feels like a stretch. Bichette was amazing in his 46-game stint (.311/.358/.571), but the ZiPS projection brings him down to .276/.335/.472 and 3.3 WAR. Vladdy Jr. needs to improve his pitch selection and launch angle to tap into his raw power. FanGraphs isn't buying the Toronto rotation -- No. 26 in projected WAR -- so the Jays will need Bichette and Guerrero to be big stars. I think that's more likely in 2021 than 2020.

Sign a big free agent

The Nationals lost Harper but signed Patrick Corbin, who went 14-7 with a 3.25 ERA and 5.7 WAR -- oh, and tossed three scoreless innings in relief in Game 7 of the World Series. Corbin was both good and expensive ($140 million). You don't always have to pay big, but most of our World Series winners made a significant addition in free agency:

2019 Nationals: Corbin (5.7 WAR)
2018 Red Sox: J.D. Martinez (6.4)
2017 Astros: Josh Reddick (4.1)
2016 Cubs: Ben Zobrist (3.7)
2015 Royals: Edinson Volquez (2.6)
2014 Giants: Tim Hudson (1.2)
2013 Red Sox: Shane Victorino (6.1)
2012 Giants: Gregor Blanco (2.1)
2011 Cardinals: Lance Berkman (3.8)
2010 Giants: Aubrey Huff (5.7)

Teams that fit here:

1. Los Angeles Angels. Back to Rendon. It's not just that Rendon is great, but that he filled a big hole in the lineup as Angels third basemen hit just .243/.306/.345 in 2019.

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2. Philadelphia Phillies. The Phillies were tied for 23rd in the majors in starting pitcher WAR last year, so Zack Wheeler fills a need, but he also has the upside to do better than the 3.96 ERA he posted for the Mets. They'll still need better results from Jake Arrieta and Zach Eflin, but Wheeler and Aaron Nola provide the starting point for a good rotation.

3. Chicago White Sox. The White Sox added Yasmani Grandal, Edwin Encarnacion, Dallas Keuchel and Gio Gonzalez in free agency. White Sox DHs hit a putrid .205/.285/.356 in 2019, so Encarnacion projects as a big improvement there, but Grandal is the big signing. With Grandal and James McCann, the White Sox project to have the best catching in the majors (5.2 WAR).

Teams that don't fit here:

1. Colorado Rockies. They didn't sign a single free agent to a major league contract.

2. Chicago Cubs. They gave $1 million deals to Jason Kipnis, Steven Souza Jr. and Hernan Perez. At least Souza could surprise. When he was last healthy, in 2017, he had a 4-WAR season for Tampa Bay.

Hey, we just had a bad season

Sure, the Nationals won just 82 games in 2018, but their talent level was obviously much higher. They had won 97 games in 2017 and 95 games in 2016. They should have won more games in 2018, as their Pythagorean record was 90-72. Based on runs scored and runs allowed, they underperformed by eight wins. This theory applies more to the Nationals than the other teams on the list, but the Astros had made the playoffs two seasons before their title year and the Giants see-sawed between championships and nonplayoff seasons.

Teams that fit here:

1. Chicago Cubs. The Cubs finished 84-78, six wins under their Pythagorean record. They were just two games out in mid-September before they collapsed with a nine-game losing streak. Also, the second-tier players were awful in 2019. Take out the core five (Kris Bryant, Anthony Rizzo, Javier Baez, Kyle Schwarber, Willson Contreras) and here's how many runs above or below average the rest of the offense was in recent seasons:

2016: minus-11
2017: plus-4
2018: plus-6
2019: minus-50

If the second-tier players aren't so awful and the bullpen is a little more clutch, the Cubs have strong bounce-back potential.

2. Boston Red Sox. The eventual champs won 108 games in 2018, and even if that was simply a year when everything came together, they also won 93 games in 2017 and 2016. Of course, bouncing back without Mookie Betts will be more difficult.

3. Colorado Rockies. Remember, they lost the division to the Dodgers in 2018 in a tiebreaker. They won a wild card in 2017. Maybe the talent level is much higher than their 71-91 performance in 2019. Or maybe it isn't.

Teams that don't fit here:

1. Philadelphia Phillies. The Phillies made all those moves last season and still finished .500. Sure, Wheeler should help, but this is neither a young team ready to make a leap (like the 2016 Cubs or 2017 Astros) nor a team just looking to bounce back from a bad season. They haven't finished above .500 since 2011.

2. Milwaukee Brewers. The Brewers actually made the playoffs last year but qualify for this article because they won 89 games. In some ways, the Brewers can be compared to the 2015 Royals, who had also won 89 games and a wild card in 2014 (and reached Game 7 of the World Series). The Royals were dismissed in part because they had lost their best starter in James Shields (14-8, 3.21 ERA), much like the Brewers are being overlooked in part because they lost Grandal and Moustakas. The Royals, however, made a lot of smaller moves in the 2014-15 offseason: adding Edinson Volquez, Kendry Morales, Luke Hochevar, Ryan Madson and then Ben Zobrist and Johnny Cueto in-season. The Brewers have similarly looked to replace Grandal and Moustakas with a series of smaller moves. Oh, and they also have an MVP candidate in Christian Yelich to lead the offense.

So who will be this year's Nationals?

Here are the three sleeper teams I like:

1. Mets (+1800, eighth). With that rotation, the likelihood of a better season from Edwin Diaz and the addition of Dellin Betances to improve the bullpen, plus Polar Bear Pete Alonso anchoring the lineup (and maybe even the return of Yoenis Cespedes), the Mets have all the ingredients ... if they don't find a way to screw it up, as the Mets so often do.

2. Angels (+2000, ninth). Do I like the rotation? Not really. Do I like the bullpen? I have some concerns. Is the AL tough at the top? Yes, it is. But the Angels have a high floor with Trout and Rendon, a potential impact rookie in Jo Adell and maybe, just maybe, Shohei Ohtani pitching like an ace come October.

3. Diamondbacks (+3000, 18th). Look, beating out the Dodgers in the NL West feels almost impossible -- FanGraphs gives the odds at just 1.9% -- and most of the projected standings have them third in the division behind the Padres. I like the depth in the rotation, however, and Ketel Marte was an MVP candidate a year ago. It's a good defensive team, Starling Marte was a solid addition and Eduardo Escobar is coming off a 35-homer season.

So, whom do you like?