As the Yankees continued to chase the Blue Jays while falling to the Mets 5-1. at Citi Field in the first of a three-game Subway Series on Friday night, this is how bad the shape of their rotation was: Michael Pineda remained in it only because Ivan Nova was more putrid.

When Pineda takes the mound on Saturday he will lug a 1-3 ledger and an obese 6.21 ERA in his previous six starts. In 33 ¹/₃ innings, he allowed 36 hits. Eight of those hits were home runs.

Those numbers should have been enough to send the inconsistent right-hander to the bullpen. Yet Wednesday in St. Petersburg, Fla., manager Joe Girardi banished Nova to the pen and inserted Adam Warren into the starting mix.

If Girardi had another starting candidate — only Bryan Mitchell is an option at this point — Pineda would have joined Nova on the walk from rotation to pen.

In his past five starts, Nova was 1-4 with a 9.23 ERA. He allowed 33 hits in 22 ²/₃ innings, walked nine and fanned a dozen. His last outing consisted of 1 ²/₃ innings against the muscular Blue Jays last Saturday in which he gave up six runs and seven hits.

“My last start I threw the ball pretty good,’’ said Pineda, who gave up four runs and six hits (three homers) in 5 ¹/₃ innings to the Blue Jays. “I made one mistake to [Edwin] Encarnacion and he hit it a home run. He is a great hitter but I threw the ball really good.’’

Pineda, who is 10-8 with a 4.25 ERA in 23 starts, failed to mention the homers he gave up to Jose Bautista and Ben Revere.

To Girardi it’s not a mystery why Pineda struggles.

“It all starts with his slider,’’ Girardi said of Pineda’s out pitch, which has been inconsistent. “I thought he threw a pretty good game against Toronto. It wasn’t that bad of a pitch to Encarnacion that he hit out. The big thing is his slider and it has to remain constant throughout. If it starts to spin a little bit during the course of the game he could be in trouble.’’