TAMPA – You would not be surprised if I told you that as of Sept. 5 last year, Dellin Betances had the second-best ERA (1.30) among the 148 relievers with at least 40 appearances, Andrew Miller was ninth (1.65) and Aroldis Chapman was 14th (1.79).

But what if I told you Chasen Shreve was 16th (1.86)?

In that same timeframe, among relievers who faced at least 175 batters, Miller (.145) and Betances (.147) ranked 1-2 in batting average against and Chapman 17th (.197). No shocker, right?

But how about if I told you Shreve was actually better than Chapman at that point, eighth among relievers at .177?

Yep, for fifth-sixths of 2015, Chasen Shreve was a heck of a reliever and then, well, then he became something less than a batting practice pitcher. In his final nine appearances, Shreve allowed 22 of the 36 batters he faced to reach safely and four homered. After allowing seven of 33 inherited runners to score over his first 50 appearances, Shreve inherited 10 runners and eight scored, and he tacked a 16.20 ERA on top of that, and a 1.594 OPS against.

The Yankees were 0-9 in those games, and Shreve was a major culprit as they barely hung on for a wild-card spot.

Unlocking what happened in the final month is an important issue for the 2016 Yankees. Because, yes, they have built this spectacular end game with Betances, Miller and Chapman. But the Yankees also arguably have the most rotation red flags of any team. So there are going to be lots of innings to cover by the bullpen.

And that is before dealing with the strong likelihood Chapman is going to miss time at the start of the season due to a suspension under the new domestic abuse protocols. Now, remove Betances or Miller for even a short DL stint and suddenly think of the number of innings needed to be filled by a middle crew minus its two most trustworthy cogs from 2015 — Adam Warren and Justin Wilson.

Which is why the Yankees tried to enlist several relievers this season and — as The Post reported last week — had a two-year agreement with Tommy Hunter before he failed their physical and the deal was squashed.

“A bullpen is not three guys,” pitching coach Larry Rothschild said. “It is seven guys out there. It is going to be important this spring to find guys to fill the other roles.”

The candidates are familiar, as so many of those who failed to hold onto roles last year are back. There is a sense among the Yankee brass that too much was asked too soon from guys such as Nick Goody, Jacob Lindgren, Branden Pinder and Nick Rumbelow, and they should be better this year for the experience.

But the only one with anything approaching a track record is Shreve, who in the first 65 appearances of his career (including his Braves debut in 2014) pitched to a 1.64 ERA. And then …

Rothschild said he may never have watched more tape on a player than Shreve’s late-season work without coming to peace with what went wrong. Brian Cashman said the internal detective work checking arm angle, velocity and spin rate showed no deviations. Shreve said this was the most he ever pitched in a season, which may have gotten him tired. He also said he started thinking about his mechanics too much and got away from just fixating on the target and throwing.

There also was this: Shreve said Brian McCann saw he was tipping pitches. And McCann said, “As a hitter, I could have picked it up,” and the catcher said he thought many hitters did. No one wanted to say publicly what the problem was, but here is something: Of those four homers Shreve gave up in his final nine outings, three came on four-seam fastballs — a pitch the lefty only used about 50 percent of the time.

“It is 100 percent fixable,” McCann said. “Let’s not forget this guy was having an unbelievable season.”

The Yankees pen sets up so much better if Shreve can be a consistent component. Joe Girardi has said he does not want to use his Big Three together often as a way to always keep at least one fresh, but that only works if someone can handle the sixth and/or seventh effectively and be trusted with late tie games on the road.

Shreve enters the leading candidate, his plus splitter making him more effective against righties than lefties and, thus, positioning him to be more than just a matchup reliever.

But only if the April-through-August Shreve resurfaces.

“You can’t let one month ruin you,” Shreve said. “I want to absolutely be the guy that this team can trust.”