We are about to find out if this extraordinary 15-2 Mets surge into postseason contention is the real deal or a cruel midsummer tease.

The schedule, with 12 of their next 15 games against division-leading teams, including six against the NL East-leading Braves, will tell the tale, but there is no denying this is a dramatically improved Mets team that was 46-54 through the first 100 games, with about the worst bullpen in baseball and a lineup that struggled for runs because of an empty hole in the No. 3 spot named Robinson Cano. What’s most interesting about this Mets turnaround is that it was accomplished without any notable contributions from Cano or Edwin Diaz, the principals in Brodie Van Wagnenen’s signature off-season trade.

A torn hamstring has mercifully ended Cano’s season while Diaz, a principal culprit in Sunday’s streak-breaking loss to the Nationals with a two-run ninth-inning homer to Victor Robles, also surrendered homers in the only two saves he recorded during the 15-2 run. Mickey Callaway can say all he wants – as he did Sunday – that Diaz “will continue to get big outs for us,” but the hard truth is he’s gotten very few of them since he started developing New York-itis at the end of May. Right now, Diaz needs to disappear, at least from high leverage situations, and maybe take some time to sit at the knee of Phil Regan for some soothing, reinforcing counseling.

And speaking of the 82-year-old Regan, his hiring as pitching coach to replace the respected Dave Eiland, June 20, roundly ridiculed by the media at the time, is now looking like the most inspired move of the embattled GM’s administration. The figures don’t lie: Under Regan, Mets starters’ ERA is the best in baseball. From Opening Day to July 24, the Met starters’ ERA was 4.27 and they averaged 5.67 innings per start. Since then, it’s 2.51 with 6.33 innings per start. Moreover, the woebegone bullpen, which had a 5.33 ERA up until July 24, averaging 4.25 walks per game, has pitched to a 3.69 ERA with 3.88 walks per game since July 24.