The Chicago Cubs have traded infielder Starlin Castro to the New York Yankees for pitcher Adam Warren and a player to be named.  (Paul Beaty/Associated Press)

NASHVILLE – After what appeared to be a dead Tuesday at the Gaylord Opryland Resort, as many as four division races were transformed by three moves in the midst of baseball’s winter meetings.

Ben Zobrist, a switch hitter who plays all over the field, agreed to a four-year deal with the Chicago Cubs, making a potent contender in the National League Central even more competitive. The Cubs then immediately traded Starlin Castro, a three-time all-star at shortstop, to the New York Yankees, a wild-card team a year ago who have now made themselves younger and faster in a very competitive American League East.

Left standing, at the moment, with Zobrist off the market: The New York Mets, who won the National League East but have a second baseman who is a free agent; and their division rival Washington Nationals, who also competed for Zobrist because he was an ideal fit for a club that could use a left-handed bat versatile enough to start at second base or fill in in left.

And, in a move that likely makes them the surprise team of the offseason, the Arizona Diamondbacks acquired right-hander Shelby Miller from the Atlanta Braves, according to Fox Sports – a deal that could catapult the Diamondbacks past the Los Angeles Dodgers and San Francisco Giants and make them favorites in the National League West even as they gave up a package that includes the top pick in last year’s draft, shortstop Dansby Swanson, according to the Arizona Republic.

Whew.

A look at how each club is affected by Tuesday’s moves:

The Cubs: When the meetings began, Chicago had three players worthy of starting for the two middle infield positions – Castro, Addison Russell and Javier Baez. Zobrist, who played his entire career up to 2015 in Tampa Bay under current Cubs manager Joe Maddon, seemed to be excess.

But the deal, which was reported to be for $56 million, allows Maddon to use Zobrist as he did in Tampa – primarily at second base, but also as a regular fill-in in left field. It makes Russell, who had bumped Castro from the starting shortstop job by the end of last season, the unquestioned shortstop headed into 2016.

According to a person with knowledge of the deal, it brings right-hander Adam Warren, a 28-year-old who can start or relieve and won’t be a free agent for three more years. Warren has a career 3.39 ERA in 147 appearances for the Yankees, 33 of them starts. He was extremely effective as a seventh-inning man in 2014, when he threw 78-2/3 innings – all in relief – with a 2.97 ERA and 1.106 WHIP. He will add meaningful depth to a bullpen with Henry Rondon and Pedro Strop at the back end.

That person said the Cubs would also receive a player to be named later, but several reports identified that player as 33-year-old utility man Brendan Ryan.

The Diamondbacks: Arizona already pulled off the most shocking move of the offseason, signing right-hander Zack Greinke to a six-year, $206 million contract to be their ace. But the Diamondbacks were determined to also snare a younger starter who is under club control (read: more affordable) for the next several years.

With the exception of Marlins lefty Jose Fernandez, the 25-year-old Miller was likely the best pitcher available to fall into that category. Forget his 6-17 record with the god-awful Braves last year. In 22 of his 33 starts, he allowed zero, one or two earned runs and finished with a 3.02 ERA in a career-high 205-1/3 innings.

The Diamondbacks already scored the second-most runs in National League a year ago, and now have a front of the rotation that can compete with those of the Dodgers (Clayton Kershaw and, for now, either Brett Anderson or Hisashi Iwakuma) and the Giants (Madison Bumgarner and Jeff Samardzija – or Matt Cain, if he’s healthy).

The Braves: Don’t roll your eyes at this fire sale at the moment. Swanson now becomes their replacement for Andrelton Simmons, who they dealt away to Anaheim for pitching prospects last month. The 21-year-old from Vanderbilt played just 22 games at low Class A after signing last summer, but he should fit perfectly for an Atlanta club that intends to compete when it moves into its new ballpark in 2017.

Almost as interesting: the Braves also bring in 25-year-old outfielder Ender Inciarte, who is coming off a season in which he hit .303 with a .747 on-base-plus-slugging percentage in a career-high 561 plate appearances. They also reportedly receive Aaron Blair, a 23-year-old right-hander who posted a 2.92 ERA in 160-1/3 innings split between Class AA and Class AAA.

The idea: for one player, the Braves landed three who could be mainstays on their 2017 major league club.

The Yankees: This is not a Yankees offseason of old. New York has not been in the mix for any of the major free agents on the board, and instead has made a pair of shrewd trades, landing outfielder Aaron Hicks from Minnesota last month and now bringing in Castro, who should team up with Didi Gregorius to make the Yankees more athletic up the middle than they have been since Derek Jeter was a much younger man.

Castro is just 26, has won three Silver Sluggers and has a very reasonable contract going forward — $40.4 million for the next four seasons, with a $16 million salary for 2020 that can be bought out for just $1 million. Yankees second basemen collectively hit .219 with a .275 on-base percentage a year ago – the second- and third-worst marks in baseball, respectively. Though Castro’s offense has been uneven in recent years – his OPS toggled from .753 to .631 to .777 to .671 over the past four years – he is sure to be an upgrade offensively.