SEATTLE >> Seattle Mariners All-Star second baseman Robinson Cano was suspended 80 games for violating baseball’s joint drug agreement.

The league announced Cano’s suspension today, a stunning development for the stalwart in the middle of the Mariners’ lineup and a club expected to contend for a postseason spot in the American League. Cano tested positive for Furosemide, a diuretic. In a statement released through the players’ association, Cano said, “This substance was given to me by a licensed doctor in the Dominican Republic to treat a medical ailment.” He said he didn’t realize it was banned.

Cano is the most prominent player to be busted since Melky Cabrera was suspended in 2012 while leading the National League in hitting. There have been 36 players suspended this year under the minor league drug program and six in addition to Cano under the big league program: Houston pitcher Dean Deetz, Washington catcher Raudy Read, Pittsburgh pitcher Nik Turley, Kansas City outfielder Jorge Bonifacio, Toronto pitcher Thomas Pannone and Minnesota shortstop Jorge Polanco.

If no games are postponed, Cano would be eligible to return Aug. 14 at Oakland.

“For more than fifteen years, playing professional baseball has been the greatest honor and privilege of my life. I would never do anything to cheat the rules of the game that I love, and after undergoing dozens of drug tests over more than a decade, I have never tested positive for a performance enhancing substance for the simple reason that I have never taken one,” Cano said in the statement issued by the players’ association.

“Today I decided to accept MLB’s suspension. This was the most difficult decision I have ever made in my life, but ultimately the right decision given that I do not dispute that I was given this substance. I apologize to my family, friends, fans, teammates and the Mariners organization.”

Furosemide, sold under the name Lasix, can be purchased without a prescription and is used to treat high blood pressure and fluid buildup. It is on the World Anti-Doping Agency’s list of banned substances.

Cano’s positive resulted from an offseason test, a person familiar with the process said. The person spoke on condition of anonymity because the agreement specifies such details remain confidential.

Because the substance involved was a diuretic, the next step was for Thomas Martin, the independent program administrator hired by the MLB and the players’ association, to determine whether the use of Furosemide was an attempt to “to substitute, dilute, mask or adulterate a specimen or in any other manner alter a test,” according to the joint drug program.

After Martin made that determination, the union filed a grievance last month. The case was scheduled to be heard starting today in Seattle before arbitrator Mark Irvings, but the union informed MLB last Friday that Cano wanted to drop the grievance and reach a settlement, the person said. MLB Senior Vice President Patrick Houlihan and union deputy general counsel Matt Nussbaum then worked to reach the agreement to accept the discipline.

It’s the first major strike in a career that has Hall of Fame potential. Cano was trending toward becoming one of the few current players with a chance to reach 3,000 hits in his career and has been a consummate defensive standout. Cano is an eight-time All-Star but now must deal with the stigma of a suspension.

“Robinson made a mistake. He has explained to us what happened, accepted the punishment and has apologized to the fans, the organization and his teammates. We will support Robinson as he works through this challenge,” the Mariners said in a statement.

The suspension comes on the heels of Cano suffering the first significant injury of his tenure in Seattle. Cano landed on the disabled list Monday after breaking a bone in his right hand after getting hit by a pitch during Sunday’s game in Detroit. He was scheduled to meet with a hand specialist in Philadelphia early today. Since 2007, Cano has played at least 150 games each season.

Cano can serve his suspension while on the disabled list but is now ineligible for the postseason should the Mariners get there and end the longest playoff drought in the four major professional sports.

If there are no games postponed, the Mariners have 11 off days during the time of the ban, so Cano would lose 91-186ths of his $24 million salary, which comes to $11,741,936.

This season, Cano was hitting .287 with four home runs and 23 RBIs in 39 games. He’s appeared healthier and quicker than the past few seasons when he’s played through leg injuries that at times limited his range.