For the first time since trading away Rickey Henderson and Mike Pagliarulo in 1989, the Yankees are sellers.

New York emphatically declared themselves sellers over the last week by trading Aroldis Chapman, Andrew Miller, Carlos Beltran, and Ivan Nova to contending teams. Beltran and Nova were both traded minutes prior to Monday's trade deadline.

The return? One big league reliever (Adam Warren), a total of 10 prospects, and two players to be named later. Among those prospects are standouts Clint Frazier (Miller trade), Gleyber Torres (Chapman trade), Justus Sheffield (Miller trade), and Dillon Tate (Beltran trade).

Frazier, Torres, and Sheffield all ranked among the top 100 prospects in baseball in Baseball America's recent midseason top 100 prospects update. Tate was the fourth overall pick in last year's draft. How much have these trades helped New York's system? Well, ask the expert, prospect guru Jim Callis:

Keep in mind that tweet is from Sunday, before the Yankees added Tate (and two others) in the Beltran trade. The gap between the Yankees and Braves systems has only grown larger.

The Braves are in the middle of a massive rebuild and have been intentionally awful the last two years, yet the Yankees have been able to build a stronger farm system in about a week by making four trades that added to their existing prospect base. They managed to keep Didi Gregorius and Dellin Betances too.

That's quite a turnaround. The Yankees didn't have to tank for two or three seasons to build a strong prospect base. They traded three rentals and an elite reliever to contending clubs. Pretty standard stuff for a rebuilding team. The Yankees did what we see a few other teams do each year.

Yankees GM Brian Cashman showed off his rebuilding chops at the trade deadline. USATSI

It goes without saying this is a very different trade deadline approach for the Yankees, who haven't had a losing season since 1992. We're used to seeing the Yankees buy buy buy. There's an entire generation of Yankee fans who know nothing but their favorite team buying. This is a new experience for thousands of 20-somethings.

Will those 10 prospects work out? That remains to be seen and that's the next part of this rebuilding phase for the Yankees. They have to turn this kids into big leaguers for this deadline to lead to the next great Yankees club. Acquiring prospects is only half the battle.

That all said, the Yankees and GM Brian Cashman showed they are not a one-trick pony this trade season. They did a complete 180 and sold off their veterans for young talent, and their major trades have been universally praised. New York has been able to salvage and otherwise disappointing season by building a dynamite farm system in short order.