It remains to be seen if there was a true shift of power in the division when the Cubs knocked off the Pirates in the National League Wild Card Game and the Cardinals in the NL Division Series, but one thing is for sure: This is baseball's most competitive division. As it stands now, here are the top three:
1. NL Central
You knew the Cardinals were going to make a move like signing Leake. They always do. That's why no division will be tougher to win in 2016 than this one.
This was true in 2015, when the Cubs won 97 games and finished third, and it should be true for the foreseeable future as the Cards, Bucs and Cubs are all built to last.
Adding Leake (at a reported five years, $80 million) puts St. Louis in position to again have the deepest staff in the Major Leagues. It's a move that probably wouldn't have been made had Lance Lynn not undergone Tommy John surgery in November, but it makes perfect sense.
Leake will pitch at 28 years old in 2016 and has made at least 30 starts in four consecutive seasons. He brings durability to a rotation that has major talents (including Jaime Garcia and Michael Wacha) with recent health concerns and didn't cost St. Louis a Draft pick, positioning the Cardinals for a major haul next June (they'll have three of the first 40 picks after losing Heyward and Lackey).
The Cubs, of course, have placed themselves on an upward trajectory that is difficult to deny. They've become a destination franchise for players, and that's not sitting well in St. Louis, which has held that distinction for a couple decades now.
Cardinals manager Mike Matheny made that point after Heyward said he picked the Cubs in part because they feature young talent while the Cards' core is aging.
"I don't think we have anything to apologize for in having a group like a [Matt] Holliday, a [Yadier] Molina, a Wainwright," Matheny told the St. Louis Post-Dispatch. "Those are the kinds of guys everybody wants on a club. … I can't say I'm in any kind of agreement with that [Chicago] core being better than any kind of core that we have. That veteran group also helps drive what the younger group turns into."
Don't forget about the Pirates. They might be the most motivated team in the NL Central after being unable to advance beyond the Division Series in three consecutive seasons. They've run into the Cubs' Jake Arrieta, the Giants' Madison Bumgarner and Wainwright in elimination games, and they haven't yet cracked the code.
Every series between these three teams in 2016 has the potential to turn into a classic. The last team standing is likely to be the one that enters the postseason favored to win it all.
2. AL Central
So you thought the Royals were a one-time wonder when they rolled to the World Series in 2014? A lot of people did. But after winning another American League pennant and the World Series title in '15, the Royals head toward '16 with pretty much everybody believing in them.
And here's the beauty of the season we're already anticipating.
While Kansas City lapped the field in the AL Central in 2015, winning by 12 games over surprising Minnesota, the club is going to be pushed next time around. The Twins, Indians and Tigers pose major threats.
The White Sox, coming off three consecutive losing seasons, probably improved more than anyone else in the AL Central, with Todd Frazier giving them another power bat they desperately need. There's a real chance they could improve from 76 wins in 2015 to 90-plus next time around.
Paul Molitor guided the Twins to a 13-win improvement in his first season as a manager, building confidence in a team that has a core of established hitters in Joe Mauer, Brian Dozier and Trevor Plouffe. All of the following come with ifs, but Miguel Sano (if he can adjust to left), Byron Buxton (if he can stay healthy for a full season) and Byung Ho Park (if he can tap into his big-time power like he did in Korea) could turn this into one of the AL's best lineups.
Cleveland allowed the second-fewest runs in the AL last season and returns the same cast. The Indians will benefit from a full season of Francisco Lindor, especially if he can duplicate his .835 OPS.
Like the NL Central, the NL West figures to be a three-team battle between old and new rivals. By signing Zack Greinke and then dealing for Shelby Miller, the D-backs demonstrated that they are very real threats to the established powers.
Cueto and Jeff Samardzija add depth to the Giants' rotation, just in time for an even-numbered year. Shortstop Brandon Crawford just keeps getting better, helping San Francisco feature one of baseball's best infields.
Dodgers president of baseball operations Andrew Friedman's quiet, patient offseason is freaking out some fans anxious for him to add more proven pitching. No matter what he does, it'll be tough to replace Greinke, but the parts are there for a huge trade at some point in the next seven months, and it seems like only a matter of time before the Dodgers do something big, which adds another level of intrigue to this race.
Phil Rogers is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.