Whether Aroldis Chapman opts out of the final two years on his five-year contract and leaves $30 million in the wind won’t be revealed until after the Yankees’ season is over.

What is known is the gas-throwing lefty closer has turned a pedestrian July into a dominant August to help the Yankees separate themselves from the Rays in the AL East standings.

Though Chapman used his slider often last year, it has played a huge part in his success this month — often making hitters look ill.

“When he throws that slider, the at-bat is pretty much over,’’ fellow lefty reliever Zack Britton said of Chapman, whose slider is thrown at 86 mph to hitters looking for a sinking fastball that has been measured at 100-plus.

Monday night the Mariners’ left-handed hitting Jake Fraley faced that problem and missed Chapman’s slider by almost a foot for a strikeout in the ninth inning. Chapman finished off his AL-leading 36th save by striking out Dylan Moore with a 102 mph fastball.

Britton has noticed hitters are no longer overpowered by velocity, which makes a secondary pitch a must.

“In this day and age, guys have no problem catching up to velocity,’’ Britton explained. “It doesn’t matter how hard.’’

Speed gun readings don’t show a big difference in velocity from July to August for Chapman, but his results sure do.

In nine July outings in which the Yankees went 7-2, Chapman recorded four saves in seven chances, gave up nine hits and walked 11 in 8 ²/₃ innings. He posted a 8.31 ERA and hitters batted .265 against him with an .847 OPS.

Chapman has worked 10 games in August with remarkably different results, including the Yankees being undefeated in his appearances. In 10 innings, he hasn’t allowed a run, given up three hits, walked three, fanned 18 and held hitters to a .091 average and a .258 OPS.