By Keith Idec

Gennady Golovkin was as surprised as anyone when Daniel Jacobs didn’t show up for the IBF’s second-day weigh-in March 18 in New York.

Jacobs never revealed that he had no intention of meeting the 170-pound limit that morning for his middleweight title fight against Golovkin that night at Madison Square Garden. Golovkin got on the New York State Athletic Commission’s scale at 169.6 pounds that morning, whereas Jacobs put on as much weight as he and his nutritionist, Chris Algieri, saw fit during the 38-plus hours that passed between the official weigh-in the morning of March 17 and the time their fight started the next night.

Jacobs (32-2, 29 KOs) estimated he weighed 178 pounds on fight night. Golovkin guessed that he weighed 170 pounds when the bell rang.

Golovkin still was able to beat Jacobs by unanimous decision in a very competitive 12-round title fight (115-112, 115-112, 114-113).

Canelo Alvarez is likely to out-weigh Golovkin (37-0, 33 KOs) when they get in the ring next month, too. Unlike Jacobs, though, Alvarez (49-1-1, 34 KOs) will adhere to the IBF’s rule that prohibits champions and challengers from adding more than 10 pounds above their division’s limit by the morning of a championship fight.

Robert Diaz, a matchmaker for Golden Boy Promotions, confirmed during a conference call Monday that Alvarez will fight for Golovkin’s IBF 160-pound championship when they square off September 16 at T-Mobile Arena in Las Vegas (HBO Pay-Per-View). They’ll also fight for Golovkin’s IBO and WBA titles, but Alvarez has been adamant about his unwillingness to fight for the WBC middleweight championship.

The IBF implemented second-day weigh-ins as safety precautions so that boxers who participate in fights for its world and regional titles are limited in how much weight they can gain by the morning after official weigh-ins. The WBA, WBC, WBO and IBO don’t conduct second-day weigh-ins.

The Mexican superstar’s beef with the Mexico City-based sanctioning organization has been going on since Alvarez declined to fight Golovkin last year and gave up the WBC’s 160-pound crown.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.