By Keith Idec

Being the “A” side has its benefits.

For Canelo Alvarez, those benefits include the knowledge that if he loses to Gennady Golovkin on September 16, he is owed an immediate rematch. According to a report published in Tuesday’s editions of the Los Angeles Times, there is a clause in the contracts for their middleweight championship showdown that stipulates Golovkin would have to fight Alvarez again in his next bout if he defeats the Mexican superstar.

Golden Boy Promotions president Eric Gomez also told the Los Angeles Times that the contract was constructed so that if Alvarez wins, he can fight whomever he wants in his following fight.

Golovkin hasn’t participated in a rematch as a professional. Alvarez defeated fellow Mexican Francisco Villanueva (14-32-3, 10 KOs, 1 NC) three times from September 2006-June 2008, but otherwise hasn’t had any rematches, either.

Kazakhstan’s Golovkin (37-0, 33 KOs) has opened as a slight favorite over Alvarez (49-1-1, 34 KOs), according to sports books throughout Las Vegas. The Westgate sports book, which sets odds on sporting events, listed Golovkin as a -160 favorite and Alvarez as a +140 underdog.

Alvarez is viewed as a very live underdog, however, because the 26-year-old challenger has shown improvement the past two years in successive victories over James Kirkland (third-round knockout), Miguel Cotto (12-round unanimous decision), Amir Khan (sixth-round knockout), Liam Smith (ninth-round knockout) and Julio Cesar Chavez Jr. (12-round unanimous decision).

Golovkin, meanwhile, had his 23-fight knockout streak halted by Daniel Jacobs on March 18, when Brooklyn’s Jacobs boxed well, withstood Golovkin’s vaunted power and nearly pulled off a huge upset at Madison Square Garden. The 35-year-old Golovkin won a unanimous decision, but by slim margins on the scorecards (115-112, 115-112, 114-113).

The long-awaited bout between Alvarez and Golovkin was announced in WWE fashion following Alvarez’s 12-round domination of Chavez on Saturday night at T-Mobile Arena in Las Vegas. Alvarez announced in the ring that a deal was in place for him to challenge Golovkin, the IBF/IBO/WBA/WBC middleweight champion.

The only thing that wasn’t announced Saturday night was the site of the Alvarez-Golovkin fight, which will be broadcast by HBO Pay-Per-View. T-Mobile Arena and the Dallas Cowboys’ AT&T Stadium in Arlington, Texas, are considered the front-runners to land the high-profile fight.

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