In a (final?) attempt to revive his career, Joba Chamberlain opted out of a minor league deal with the Blue Jays after not pitching very well and signed a minor league pact with the Royals.

He did so because the Royals had shown interest in him previously and because Kansas City is close to his Nebraska roots. But he mainly did so because Royals pitching coach Dave Eiland knows Chamberlain so well, with first-hand knowledge of what Chamberlain looked like when he was great.

Eiland was the Yankees minor league pitching coordinator in 2006 when Chamberlain was drafted and his pitching coach with the Yankees from 2008 to 2010 when there were Rules for how to use the righty and controversy over whether those Rules — and bouncing him between the rotation and pen — were diminishing his effectiveness and health.

Chamberlain had pockets of success on top of traumatic injury and diminishing stuff. He never fulfilled the great aspirations. And in some ways, it is easy to forget just how stupendous he was in his major league debut in 2007, when he helped the Yankees make the playoffs by performing in a short span in a way that perhaps even Mariano Rivera or Dellin Betances never matched: 24 innings, one run (0.38 ERA), 34 strikeouts, a .145 batting average against.

Then the midges got Chamberlain and the Yankees in the playoffs in Cleveland.

Still, at minimum, Chamberlain appeared headed for an elite relief career. Yet what if I told you the Yankees’ 2006 draft class holds the best relief group in history — and it doesn’t include the first-rounder Chamberlain, who also was released by the Tigers earlier this year?

Would you take your five main relievers combining for a 1.95 ERA over 272 2/3 innings while averaging 9.84 strikeouts per nine innings and a .195 batting average against? That is what the quintet of Cleveland’s Zach McAllister (drafted in the third round by the Yankees in 2006), San Francisco’s George Kontos (fifth round), Betances (eighth round), Pittsburgh’s Mark Melancon (ninth round) and the White Sox’s David Robertson (17th round) have done this year.

Melancon, Robertson and Betances have proven themselves over multiple seasons as belonging among the majors’ best relievers. Kontos has worked his way over the past few years into a more prominent role for the Giants. He has a 2.91 ERA over the last four years (175 appearances) since being dealt to San Francisco for Chris Stewart. McAllister finally appears to have found his niche as a power reliever after failing as a starter (kind of like Betances).

There are 20 relievers averaging more than 11 strikeouts per nine innings (minimum 40 relief appearances), and that group includes Betances (14.1), Robertson (12.4) and McAllister (11.3). There are just 38 pitchers who have thrown at least 45 innings of relief with an ERA below 2.90 and a WHIP below 1.20: Betances, Kontos, McAllister, Melancon and Robertson are among them. So is Tyler Clippard, drafted by the Yankees in 2003.

It underscores that while the Yankees have struggled in other areas, they have excelled at producing good major league relievers. And Colorado’s Tommy Kahnle and Atlanta’s Arodys Vizcaino, who are getting looks at closer down the stretch this season, can be added to the list.