Ben Zobrist joins the Cubs, who send Starlin Castro to the Yankees

The stove is officially hot. Human Swiss Army knife Ben Zobrist has signed with the Chicago Cubs, who have in turn traded Starlin Castro to the Yankees for Adam Warren and Brendan Ryan. Both teams have gotten new second basemen in the deal, while the Cubs also get a valuable arm in Warren, who can both start and be useful in high-leverage relief situations.

At its most basic level, the series of moves is about the second base position for both teams. Castro is under contact through 2019 and just 25 years old, yet the Cubs seemed to have tired with his inconsistencies and low-OBP approach at the plate. Castro has just a .321 OBP over the course of his career and managed just a .291 mark this year. That doesn't reflect the .319 he posted after the All-Star break as his bat came back to life and he flourished after a move to second base.

Castro has always been a naturally talented player, and this is what the Yankees are gambling on. Zobrist, meanwhile, has a .355 career OBP and offers the positional flexibility that Cubs manager Joe Maddon adores. Though he's going to be 35 next year, Zobrist's 4-year $56 million deal is relatively cheap for a player of his acumen, and especially one that's aged so well.

The move to acquire Castro is one that falls into a recent pattern of Yankees transactions. For the first time in a while, the AARP-eligible Yankees seem to actively be getting younger. Didi Gregorius, Nathan Eovaldi, Chasen Shreve, Aaron Hicks and Castro will all be 26. Luis Severino will be 22. Greg Bird and top outfield prospect Aaron Judge will be 24. Michael Pineda will be 27. There's a small army of 20-something relievers that can be shuttled between the Bronx and Triple-A.  And with Mark Teixeira's money coming off the books following the 2016 season, the Yankees will have even more room to play. The Yankees have reportedly not discussed Severino, Bird or Judge in any trade discussions. Youth and sustainability is the clear goal for Brian Cashman. It's unclear if pigs have been seen taking flight.

Yankees haven't had a regular starting middle infield this young since Bucky Dent and Willie Randolph.

— Jeff Quagliata (@yestoresearch) December 9, 2015

The big question is whether or not Castro's bat can stay productive, and whether he'll be better than the Rob Refsnyder/Dustin Ackley platoon. In 2014 Castro was a 117 wRC+ player, but in 2013 he was at 74 wRC+. Who is the real Castro?

Steamer projects a 94 wRC+ for Castro next year, which is perfectly fine for a middle infield player. If the Yankees can squeeze league average offense and fair fielding out of Castro, that's a win. A big win. They may be able to do it, too. New assistant hitting coach Marcus Thames has been groomed for the job for years now, and he'll also have Alex Rodriguez whispering in his ear.

As for the incumbents, Refsnyder's glove is suspect at best and while Ackley faired well at the plate in his limited time in pinstripes there's no way to be sure that it will be sustained. Even without a platoon role, Ackley will still provide positional versatility and a lefty bat on the bench. Refsnyder can either be stashed in Triple-A or punted in a trade. Warren and Ryan are not very much to give up for a player with Castro's talent. It's a gamble, but it's one that the Yankees are happy to make. Putting that much value into a 35-year old is the gamble that the Cubs made.

How well will Zobrist age, for that matter? Though his 2015 wRC+ of 123 was his best since 2012, his defensive metrics took a steep dive. One defensive run saved at second base turned into -7 DRS. 6 DRS in left field became -5 DRS. That's not surprising for a player of Zobrist's age and the injury he suffered in 2015. Many players continue to hit well while their defense declines. Like hitting, defense is a thing that can fluctuate from year to year, and it's entirely possible that Zobrist goes back to being quite good at catching the baseball in 2016.Given his age, though, it's not particularly likely.

Zobrist will likely be perfectly useful and impactful second baseman for the Cubs in 2016. It's what happens in 2018 and 2019 that could make this deal look bad. Zobrist was worth 5.5 fWAR in 2014 and 2.1 fWAR in 2015. His decline is coming. The Cubs will need to capitalize quickly. It's a good thing then that they have a nuclear offense, a strong starting rotation and a quietly effective bullpen that just got even better with the addition of Warren. They won't have any issues capitalizing on Zobrist while they can.

What happens next is key. The Cubs may still yet add an outfielder and another starting pitcher, and the Yankees also need a starter. Zobrist was also said to be the plug in the dam that was holding back the flood of position player signings. The markets for Jason Heyward (rumored to be a Cubs target), Justin Upton, Yoenis Cespedes and Daniel Murphy may soon start to materialize. Between this trade and the bonkers Shelby Miller deal, the offseason and Winter Meetings are now truly in full swing. So buckle up, grab some popcorn, and open up Twitter and MLB Daily Dish. The stove is hot. The winter is still young. Your team could be next.

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Nicolas Stellini is a featured writer at Beyond the Box Score. He also covers the Yankees at BP Bronx. You can follow him on Twitter at @StelliniTweets.