When Zack Wheeler entered the game in the third inning of the Mets’ spring training opener yesterday, the temperature at Tradition Field read 86 degrees.

It was about to get hotter.

The blazing right-hander turned up the heat. A few more spring outings like this, and Wheeler will be forcing the Mets’ hand to put him in the starting rotation right now.

Forget Vegas, start at Citi Field.

Wally Backman, who was a young second baseman when Doc Gooden made his Mets debut in 1984, told The Post what Mets fans have been longing to hear:

“He’s very similar to Doc,’’ Backman said of Wheeler. “I think Doc’s breaking ball was a little bit bigger, but this kid has got, to me, real high expectations.’’

Yesterday was but a two-inning taste. Just wait.