The Rays, Astros, Indians, A’s and Twins began the weekend ranked 1-5 for best ERAs in the AL. The Yankees were sixth.

That feels revelatory because the Astros, Yankees and Twins are probably winning division titles, and the two wild-card spots will come from the Rays, Indians and A’s.

But the gap from the Rays in first to the Twins in fifth was sixth-tenths of a run, or close to what it was from the Twins in fifth to the Yankees in sixth — a .45 gap.

That too feels instructive. The perception is the Yankees have built the majors’ best record with lineup and bullpen depth covering for rotation fallibility. The sense is that is what will have to occur come October for the Yanks to secure their 28th title.

But there is no script. The 2015 Royals finished 12th in the AL in rotation ERA and won the World Series because of, yes, the strong pen, but also because after all the post-trade worries Johnny Cueto delivered a few brilliant efforts in October, and so did Edinson Volquez. The 2014 Giants were 10th in NL rotation ERA and received perhaps the greatest postseason pitching performance ever from Madison Bumgarner.

Did anyone see Jeff Weaver and his 5.76 emerging as a postseason star in 2006 when the Cardinals — 12th in the NL in ERA — won it all?

And there were the 1996 Yankees, whose 4.96 rotation ERA was sixth in the AL and still second-worst in Yankees history. But ace David Cone got healthy in time, after missing four months, and Jimmy Key found his health and best self to join Andy Pettitte to provide a strong starting trio. The deep bullpen and lineup was needed only to cover for Kenny Rogers, who lasted a total of seven innings in three postseason starts with a 14.14 ERA.

Stunning: The Yanks won all three of those games.

The Yanks beat an Atlanta team in the World Series that with Tom Glavine, Greg Maddux and John Smoltz presented a trio that had a starting edge at least as substantive as what Houston would present with Gerrit Cole, Zack Greinke and Justin Verlander, should the Astros and Yankees make it to the ALCS.

Could ace Luis Severino, due to throw his first major league pitch Tuesday, be this year’s Cone, back in time to make a difference? Can Masahiro Tanaka be Key — a savvy, unflappable navigator of postseason lineups (Tanaka has a 1.50 ERA in five postseason starts)? Can Paxton, who has emerged as the ace as the season has gone along as fellow lefty Pettitte did in ’96, have a moment like Pettitte did against Smoltz that season and go pitch for pitch with a Cole or Verlander?

Happ is a wild card, in part because of his left biceps injury announced after his Thursday outing in Detroit. But in his five previous starts, Happ appeared to regain the location and effectiveness of his up-in-the-zone fastball. In that period hitters were 3-for-45 in at-bats ending in his four-seam fastball.

If the Yankees have that guy, there is a chance for four competent-or-better starters. If not, like with fellow lefty Rogers in ’96, the Yanks may have to win in spite of poor work from a starter (both Rogers in ’96 and Happ this year were 12-8, producing winning records because of the excellence around them). The Yanks used the same formula in 2000 with Roger Clemens, Orlando Hernandez and Pettitte carrying the rotation while another lefty, Denny Neagle, struggled.

Or it is possible this year that the Yanks bypass a fourth starter in favor of an opener such as Chad Green or CC Sabathia.

Whomever starts, manager Aaron Boone seems to have learned from last year when, in particular, he had a slow hook for Severino in Division Series Game 3 against the Red Sox. The Yankees skipper will probably allow starters go if they are performing well or the Yankees are up big, dictating that length should be permitted.

But the Yanks also appear determined to play tournament baseball and use whatever number of pitchers necessary per game to try to win. The Yanks were 24-0 when Aroldis Chapman, Zack Britton, Tommy Kahnle and Adam Ottavino all appeared in a game. Can Dellin Betances return in time and be effective enough to create a Big Five?

Since the beginning of August, Green has had one bad performance in 13 and even with that had held opponents to a .154 average and struck out 30 in 20 ¹/₃ innings. Domingo German has two relief outings this season, covering six shutout innings in which hitters are 2-for-21 with nine strikeouts and no walks.

The Yankees will hope their 10 or 11 pitchers as a group outperform opposing staffs — and, if necessary, mask any rotation problems.

The big worry would be home runs. The Yankees hit more than any team. But their starters’ 1.81 per nine innings were second worse only behind the pathetic Orioles (2.07). German, Sabathia, Happ and Green have been particularly bad when starting — though only one is likely to start in a playoff series if Severino is healthy — while Paxton and Tanaka have been MLB average (recognizing the league average is the highest ever).

In the last quarter century — a period in which they have had only winning records — a Yankees rotation has had a worse ERA than the 4.62 of this group going into the weekend three times. In 1996 and 2000 enough of the rotation rallied to help win titles. In 2004, Hernandez could not stay healthy, and Kevin Brown and Javier Vazquez were team killers, and the Yanks allowed the Red Sox to rally from a three-games-to-none deficit to win the AL pennant.

What will this group of starters author?