The best sign a trade works for both teams is if you undid the deal, the players would be valuable to their old teams — yet their old teams still would not undo the trade.

The November 2015 swap that sent Andrelton Simmons from the Braves to the Angels for Sean Newcomb is such a transaction. As badly as the Angels would love to have further rotation depth, they would prefer to have Simmons, a shortstop who might be the best defensive player in the game and has blossomed offensively (.329).

Meanwhile, though Simmons would be an upgrade from Dansby Swanson at short for Atlanta, Swanson is a good player, and Newcomb has better harnessed his excellent stuff and has been the best starter (5-1, 2.39) on a first-place team. The lefty is 4-0 in May, having yielded one run in 25 innings.

This weekend was yet another referendum on which way the game is skewing when it comes to age. Jose Bautista, 37, was released after a failed audition, of just 12 games, with the Braves, who will now double down on yet another young player in Johan Camargo, 24, at third with Austin Riley, 21, on the horizon.

The only players in their age-36 or older season who have played in even 30 games this season are Nelson Cruz, Rajai Davis, Ian Kinsler and Albert Pujols. This after an offseason when teams mostly shunned older hitters.

Until this weekend, Atlanta had deployed the three youngest players in the majors: Ronald Acuna, Mike Soroka and Ozzie Albies — and lefty Luiz Gohara was sixth. But then, to try to overtake the Braves in the NL East, the Nationals summoned 19-year-old Juan Soto , who began this season at Low-A (16 games), followed by High-A (15) and Double-A (eight). In all, he hit .362 with 14 homers and a 1.211 OPS and now has a chance to be Washington’s regular left fielder — in his first start Monday, he hit a three-run homer.

It also adds further pressure for the Blue Jays to call up the consensus No. 1 prospect in the minors, Vladimir Guerrero Jr., who at 19 in Double-A is hitting .421. The Blue Jays, though, have Josh Donaldson playing his position (third), an expensive DH they don’t yet want to give up on (Kendrys Morales) and continue to insist they want Guerrero to keep working on his defense and perhaps experience some failure and show he can rebound before being called up.