The New York Yankees, second in the AL East by 12 games and starting to string together carefree Octobers, on Friday signed left-handed reliever Andrew Miller to a four-year, $36 million contract.

It would be the largest contract ever given to a set-up man, unless Miller overtakes Dellin Betances and becomes the closer, at which point that’s still a lot of years and a lot of money, to which the Yankees are prone.

Still, many viewed Miller as the best reliever on the market. Those who disagree, coincidentally, cite David Robertson, the apparently outgoing Yankees closer who saved 39 games in his first – and likely only – season as Mariano Rivera’s replacement.

A failed starter who was non-tendered by the Boston Red Sox just four years ago, Miller, 29, found his groove as a reliever. He posted his best season in his lead-up to free agency, last year posting a 2.02 ERA and 0.802 WHIP (along with 14.9 strikeouts per nine innings) in 73 appearances with the Red Sox and Baltimore Orioles. He was about as effective – which is to say, very – against right-handed hitters as he was against left.

The Yankees are believed to have won out over the Houston Astros and, to some degree, the Los Angeles Dodgers. The Dodgers, whose bullpen was at best unreliable in 2014, were wary of bidding more than three years.

So, on the same day, the Yankees acquired a defense-first shortstop in Didi Gregorius and a formidable back-end reliever in Miller, which shouts “run prevention.” In front of Betances and Miller (or, perhaps, Miller and Betances), they’ll have similar big arms in Justin Wilson, Shawn Kelley, Esmil Rogers and Adam Warren. The bullpen, even without Robertson, should be very good.

For all Miller has done well over the past three seasons, or since becoming a full-time reliever, he has one career save. It has not, perhaps until now, been in his job description, though he has the command (2.5 walks per nine in ’14) and the stuff (big fastball, wipeout slider) to pitch wherever the Yankees put him.

The Yankees still would seem to be short a starting pitcher or two and perhaps that is where they turn next, with Max Scherzer, Jon Lester, James Shields, Brandon McCarthy and Ervin Santana, among others, still available.

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