Seattle Mariners second baseman Robinson Canó, an eight-time MLB All-Star and one of baseball’s highest-paid players, has been suspended 80 games after testing positive for a banned substance.

The office of the commissioner of baseball announced on Tuesday that Canó was suspended without pay effective immediately after testing positive for furosemide, a weight-reducing diuretic also believed to be a masking agent, in violation of Major League Baseball’s joint drug prevention and treatment program, a stunning development for the stalwart in the middle of the Mariners’ lineup and a club expected to contend for a playoff spot in the American League.

Canó, 35, said in a statement issued on Tuesday through the Major League Baseball players’ association that he “decided to accept the MLB’s suspension” despite receiving the substance from a licensed doctor in his native Dominican Republic to treat a medical ailment which he did not disclose.

“While I did not realize at the time that I was given a medication that was banned, I obviously now wish that I had been more careful,” Canó said.

He added in the statement: “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.”

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 on Tuesday 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 Houlian and union deputy general counsel Matt Nussbaum then worked to reach the agreement to accept the discipline.

If no games are postponed, Canó would be eligible to return 14 August at Oakland.

It’s the first major strike in a career that has Hall of Fame potential. Canó 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, 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.

Canó is in the fifth season of a 10-year, $240m contract with Seattle which he signed in December 2013 after nine prolific years with the New York Yankees. His loss of salary during the suspension is expected to be around $11m.

The timing of the suspension comes on the heels of Canó suffering the first significant injury of his tenure in Seattle. Canó 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 Tuesday.

Canó 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.

He is batting .287 with 23 RBIs and 10 home runs in 39 games played this season for the Mariners, who are currently in third place in the AL West, one and a half games behind the division-leading Los Angeles Angels. He’s appeared healthier and quicker than the past few seasons when he’s played through leg injuries that at times limited his range.

The use of furosemide led to the expulsion of Bulgaria’s entire weightlifting team from the 2000 Sydney Olympics, which included the stripping of two medalists: men’s bronze winner Sevdalin Minchev and Izabela Dragneva, the first women’s weightlifting champion in Olympic history.

Canó 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 Canó 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.