As soon as the Astros closed out a stirring seven-game World Series by bringing home the first title in franchise history, the questions began.
Can they do it again next year and become the first repeat World Series winner since the Yankees did it in 1999 and 2000? And what about those Yanks, by the way? Will they be good enough next season to beat this Astros team, which eliminated them in the American League Championship Series?
And what about those oh-so-close Dodgers? Will they get it done in 2018?
Meanwhile, how good will the Cubs, Indians, Nationals and D-backs be? And can someone else jump up and stun everybody with a dramatic turnaround season?
Yes, the end of the last game in 2017 means the beginning of the flood of speculation about what might happen this spring all the way to next October.
With that in mind, here is a breakdown of the top World Series contenders for 2018.
THE FAVORITES
Astros
2017: 101-61, won World Series
Key free agents:Luke Gregerson, Cameron Maybin, Carlos Beltran, Tyler Clippard, Francisco Liriano
Why they could win: The Astros retain their sensational homegrown core of Jose Altuve, Carlos Correa, George Springer and Alex Bregman, and they feature enviable offensive depth (Yuli Gurriel, Marwin Gonzalez) plus solid starting pitching (Justin Verlander, Dallas Keuchel and Lance McCullers).

Offseason questions: It's possible that general manager Jeff Luhnow will focus on improving the team via pitching. Expect Houston to try to bolster its starting rotation and bullpen via trades or free agency, and it has the payroll flexibility and Minor League system to do so.
Dodgers
2017: 104-58, lost World Series
Key free agents:Yu Darvish, Brandon Morrow, Tony Watson, Chase Utley, John Forsythe ($8.5 million club option with a $1 million buyout), Curtis Granderson, Andre Ethier, Franklin Gutierrez

Why they could win: Not only do the Dodgers still have Clayton Kershaw, Kenley Jansen, Rich Hill, Alex Wood and the potent mix of veteran and young hitters featuring Justin Turner, Corey Seager, Cody Bellinger, Yasiel Puig and Chris Taylor, but they've got the experience of winning the National League pennant and the farm system to make deals to plug any holes.
Offseason questions: Will they re-sign Darvish, and if not, who will replace him as a No. 2 starter? Also, how will they restock the bullpen and how will young starter Julio Urias recover from his shoulder injury?
Indians
2017: 102-60, lost in AL Division Series
Key free agents:Jay Bruce, Carlos Santana, Bryan Shaw, Joe Smith, Austin Jackson

Why they could win: A team that won 22 consecutive games is in perfectly good shape, despite an earlier-than-expected postseason exit, and the Tribe has a solid starting rotation and an October-tested roster returning largely intact. The Indians also will be motivated to get back to the World Series after being eliminated by the Yankees in 2017.
Offseason questions: The Indians will have to decide how to proceed with the expiring contracts of Bruce, Santana and Shaw, key contributors to their astonishing regular-season run. They'll also have to find continuity with a new pitching coach after Mickey Callaway was hired to manage the Mets.
Yankees
2017: 91-71, lost in ALCS
Key free agents:Carsten Sabathia, Todd Frazier, Matthew Holliday, Michael Pineda, Jaime Garcia

Why they could win: They are young, dangerous, improving ahead of schedule and loaded with one of the best farm systems in the game. The emergence of Aaron Judge, Gary Sanchez and Luis Severino as young stars plus a lockdown bullpen helped get them to within one victory of the World Series.
Offseason questions: The departure of manager Joe Girardi after 10 years at the helm presents a degree of uncertainty, and GM Brian Cashman will have to work to patch up his starting rotation, but the prospect-rich Yanks are well positioned for the Hot Stove season.
THE CHALLENGERS
Nationals
2017: 97-65, lost in NLDS
Key free agents:Jayson Werth, Howie Kendrick, Brandon Kintzler, Matt Albers, Edwin Jackson, Oliver Perez, Joe Blanton, Stephen Drew, Jose Lobaton

Why they could win: With Bryce Harper, Anthony Rendon, Daniel Murphy, Ryan Zimmerman, Trea Turner, Max Scherzer and Stephen Strasburg all returning, the Nationals have as much talent on their 25-man roster as anyone in MLB. The Nats are coming off an excellent 2017 regular season and are due to bust out in October one of these years.

Offseason questions: The Nationals still haven't won a postseason series despite running away with the NL East. Now, they bring a new manager, Dave Martinez, into the clubhouse, and will likely say goodbye to a handful of veteran players who had influence therein. It will be up to GM Mike Rizzo to find the right mix of replacements while continuing to shore up the bullpen.
Cubs
2017: 92-70, lost in NLCS
Key free agents:Jacob Arrieta, Wade Davis, John Lackey, Alex Avila, Koji Uehara, Brian Duensing

Why they could win: They are still very young and very good. The position players, led by Kristopher Bryant and Anthony Rizzo, are capable of scoring a lot of runs, and young players such as Willson Contreras and Albert Almora Jr. are emerging as potential stars. The starting rotation still features the terrific trio of Kyle Hendricks, Jose Quintana and Jonathan Lester.
Offseason questions: Who will fill out a starting rotation that looks like it will have two big vacancies? And how will club executives Theo Epstein and Jed Hoyer go about improving a bullpen that ran out of gas in the team's NLCS loss to the Dodgers?
D-backs
2017: 93-69, lost in NLDS
Key free agents:J.D. Martinez, Fernando Rodney, Chris Iannetta, Jorge De La Rosa, Adam Rosales, David Hernandez

Why they could win: The combination of perennial NL MVP Award candidate Paul Goldschmidt, A.J. Pollock and Jake Lamb will strike fear into any opposing pitching staff, and Arizona has a quality starting rotation of its own in Zack Greinke, Robbie Ray, Zack Godley, Taijuan Walker and Patrick Corbin.
Offseason questions: If the D-backs don't reunite with Martinez, and that's a possibility considering that the slugger will be coveted by many clubs and is bound to land a significant long-term deal, they'll have to find a way to replace the huge boost of offense he provided down the stretch. The club also could look to bolster its bullpen.
Red Sox
2017: 93-69, lost in ALDS
Key free agents:Eduardo Nunez, Mitch Moreland, Doug Fister, Chris Young, Addison Reed, Rajai Davis, Fernando Abad

Why they could win: They are young and explosive on offense, with a formidable combination of speed and power in the form of Mookie Betts, Andrew Benintendi, Xander Bogaerts and Rafael Devers, and they are stacked in the starting rotation with AL Cy Young Award contender Chris Sale plus former Cy Young winners David Price and Rick Porcello and Thomas Pomeranz. They're also strong in the late innings with closer Craig Kimbrel.
Offseason questions: Price's health is a big question, and so is the managerial situation with former player Alex Cora now taking the reins after the departure of John Farrell. More uncertainty looms in the bullpen, where the Red Sox could be looking to rearrange roles over the offseason.
THE HOPEFULS
Twins
2017: 85-77, lost in AL Wild Card Game
Key free agents:Matt Belisle, Bartolo Colon, Hector Santiago, Glen Perkins, Dillon Gee

Why they could win: The offense caught fire in the second half of the 2017 season and did so largely without the services of its premier power hitter, Miguel Sano, who was injured and is set for shin surgery. That bodes well for 2018, and the Twins shouldn't lose too much from an improving roster via free agency.
Offseason questions: The Twins would surely like to improve a starting rotation that had its share of inconsistency in '17, and they might want to shore up their relief pitching while they're at it.
Rockies
2017: 87-75, lost in NL Wild Card Game
Key free agents:Carlos Gonzalez, Mark Reynolds, Greg Holland, Jonathan Lucroy, Pat Neshek, Tyler Chatwood, Jake McGee

Why they could win: Well, for starters, they've got two of the best players in the Majors in Nolan Arenado and Charlie Blackmon. The return of a healthy David Dahl could provide a nice boost, while Tyler Anderson and Kyle Freeland showed enough for fans to be excited about the direction of the starting rotation.
Offseason questions: Perhaps no team has more free agents-to-be that contributed as much offense as Gonzalez, Reynolds and Lucroy did while they were at their best in 2017. And the Rockies could have to supplement their young starters and relievers with some veteran additions.
Cardinals
2017: 83-79, missed playoffs
Key free agents:Lance Lynn, Juan Nicasio, Seunghwan Oh, Zach Duke

Why they could win: Young and exciting arms (Carlos Martinez, Luke Weaver) mixed with tested veterans (Adam Wainwright, Michael Wacha) give manager Mike Matheny a quality starting rotation, and the club still has its share of offensive thump with Matt Carpenter, William Fowler and Jedd Gyorko, along with breakout hitters Paul DeJong and Tommy Pham.
Offseason questions: The team struggled with late-inning relief and might want to add there while shopping for more pop for its lineup, which finished 27th in the Majors in slugging percentage in 2017. New pitching coach Mike Maddux will use Spring Training to try to get off to a good start with his charges.
Brewers
2017: 86-76, missed playoffs
Key free agents:Neil Walker, Matt Garza, Anthony Swarzak, Wily Peralta

Why they could win: The Brewers came together for manager Craig Counsell in a big way in 2017, with Travis Shaw, Eric Thames, Domingo Santana, Chase Anderson and Corey Knebel all busting out with career years. GM David Stearns also figures to have some payroll flexibility this offseason, which could help strengthen the roster.
Offseason questions: Will Orlando Arcia blossom into the star the Brewers have always thought he'd be? Will Jonathan Villar play like he did in his breakout season in 2016? Is prospect Lewis Brinson ready to shine at the big league level? And how will Milwaukee improve the starting rotation and bullpen to get the team into October?
THE FIELD
Rays: They have decisions to make regarding their immediate future, but there's a lot of talent there, particularly with young starters Chris Archer and Blake Snell, along with outfielders Corey Dickerson and Kevin Kiermaier.
Angels: They have the best player in baseball in Michael Trout and a talented and deep starting rotation if it can return from the multiple injuries that have plagued it over the last two years.
Mariners: They need their starting pitching to return to health, but any time a team has Robinson Cano, Nelson Cruz and Kyle Seager in the heart of its order, it has a chance to do big things.

Mets: If Matt Harvey can return to form and Noah Syndergaard and Jacob deGrom stay healthy, New York can bounce right back into contention in the NL East under new manager Callaway.
Braves: They lost 90 games in 2017, but the Braves are loaded with exciting young players and prospects, and they could be on a sharp improvement curve. They're worth keeping an eye on in '18.