Each December, New York Yankees owner Hal Steinbrenner and GM Brian Cashman give their team’s fans plenty of holiday cheer. But how they've done it this Christmas is nothing short of astounding.

Over the past three years, and most notably over the past 24 months, Cashman has turned an aging and decaying roster into one of the most envied in the game. What stands out is how the Yankees GM, with help from Steinbrenner’s financial might and stars like Aaron Judge, Gary Sanchez and Luis Severino emerging from the farm system, has turned a stocking full of coal into solid gold.

Beginning with the Didi Gregorius deal in December 2014, this is the before-and-after of his main trades (because Cashman re-signed Aroldis Chapman and got Starlin Castro for essentially nothing -- we’ll explain below -- we are leaving them out of the players he dealt, despite Castro's role in the Giancarlo Stanton trade):

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Cashman dealt: Andrew Miller, Brian McCann, Carlos Beltran, Brendan Ryan, John Ryan Murphy, Shane Greene, Rookie Davis, Eric Jagielo, Caleb Cotham, Tony Renda, Jorge Guzman and Jose Devers.

And he got back: Stanton, Chapman, Gregorius, Gleyber Torres, Albert Abreu, Aaron Hicks, Clint Frazier, Justus Sheffield, Adam Warren, Billy McKinney, Dillon Tate, Nick Green, Erik Swanson, Ben Heller, J.P. Feyereisen and Rashad Crawford.

Here's how he did it:

Flipping and re-signing Chapman: Just after Christmas in 2015, Chapman was being investigated by police and Major League Baseball on allegations of domestic violence. The news scuttled a potential trade of Chapman from the Cincinnati Reds to the Los Angeles Dodgers.

The Reds, noncontenders not interested in paying a closer more than $11 million, dealt Chapman to the Yankees for the discount price of four middling prospects. Davis has an 8.63 ERA in 24 major league innings and Renda batted .183 in 32 big league games in 2016, while Jagielo hit .204 between Double-A and Triple-A this year and Cotham is no longer in the Reds organization.

Meanwhile, Cashman flipped Chapman that July to the Cubs in a trade that netted Torres -- considered one of the top five prospects in the game, who might start at second or third in the majors this season -- McKinney, who has major league potential, Warren and Crawford, who is at Double-A. In the offseason, Cashman signed Chapman for five years and $86 million. If Torres turns into an All-Star -- and putting aside the Chapman moral question at the time of that initial trade -- these are historic transactions.

Moving Miller: The one premium major league player Cashman has traded is Andrew Miller. With 2.5 years remaining on his contract in July 2016, Cashman was able to extract Frazier and Sheffield and two other prospects from the Cleveland Indians. Frazier shows signs on the major league level that he could be something special, while Sheffield is projected as a No. 1 or No. 2 starter.

This was the biggest value-for-value trade Cashman has made, but it's one he'd likely make again, because he could flip Frazier to get more pitching, and Sheffield might end up as good as, if not better than, Miller.

Founding Stanton Island: Cashman again took advantage of the Dodgers' not making a deal. With new Marlins CEO Derek Jeter orchestrating a fire sale in South Florida, Stanton wanted to go to the Dodgers, first and foremost. Jeter and his executives instead tried to trade Stanton to the Giants or Cardinals. While Stanton said no, the Dodgers, over the luxury tax threshold, had no match with the Marlins -- unless Miami would take money back in a trade. Jeter wouldn't.

So Cashman put together a package of Castro and two relatively unknown Single-A players, Guzman and Devers.

Incidentally, Guzman was acquired a year ago in the McCann trade with Houston, which also netted Abreu, a 22-year-old righty with 100 mph stuff who is fast becoming one of the better prospects in the game.

Castro, as it turned out, was basically acquired for nothing, though the Yankees had to take on the $38 million and four years remaining on his contract. They added Castro in a December 2015 swap with the Cubs for Ryan and Warren. The Yankees were going to cut Ryan before 2016 and then went on to re-acquire Warren with Torres as part of the Chapman trade with the Cubs.

That's why we left out Castro from the give-and-take above, even though he could really be considered another plus for Cashman since he was productive as a Yankee and even made the All-Star team last year.

Buying low on Gregorius and Hicks: Cashman and his crew were just smarter in trades for Gregorius and Hicks. Gregorius looks like he might be an All-Star, which makes trading Greene for Gregorius look brilliant. Yankees super scout Tim Naehring identified Gregorius as a potential replacement for Jeter after 2014, even though Gregorius had been on two teams by the time he was 24 and had shown an inability to hit lefties.

Meanwhile, Hicks for Murphy is good on the surface but even better when you consider Murphy didn’t pan out in Minnesota. Cashman & Co. come off as especially savvy because, in his year with the Yankees, Murphy looked as if he might be a quite serviceable backup catcher. The Yankees chose to cut bait in exchange for the former Twins top prospect.

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At least a third of next year’s starting lineup -- Stanton, Gregorius, Hicks and possibly Torres -- will be a result of these trades, while Chapman and Warren will be vital bullpen pieces. Meanwhile, Sheffield could become a top starter in the coming years, maybe even getting a chance in 2018. Frazier could be in line to be a starting outfielder, if he isn't flipped for pitching first. Abreu could be used in a trade, or the Yankees might wait and see whether his talent can carry him to the Bronx.

The only true major league contributors dealt were Miller, McCann, Greene and Beltran, who retired after winning a title this year in Houston.

Last season, Cashman made trades for veterans and used his farm system to his advantage. He acquired Sonny Gray for three top prospects, pitcher James Kaprielian, speedster Jorge Mateo and outfielder Dustin Fowler. In that trade, Cashman received $1.5 million in international signing money, which was designed to go to the Babe Ruth of Japan, Shohei Ohtani, who ultimately didn’t want any part of the Bronx. Cashman also reacquired reliever David Robertson, along with third baseman Todd Frazier and reliever Tommy Kahnle for Tyler Clippard and three prospects, left-hander Ian Clarkin and outfielders Blake Rutherford and Tito Polo. Though the players Cashman dealt do have potential, these deals have been good for the Yankees so far.

On top of all this -- and perhaps equally as, if not more, impressive -- Cashman has put the Yankees in place to fall under the luxury-tax threshold by the end of next season.