LOS ANGELES -- Marlins second baseman Dee Gordon, the reigning National League batting champion and a two-time All-Star, has been suspended by Major League Baseball for 80 games without pay for violating the league's drug policy.

The Office of the Commissioner of Baseball levied the suspension after Gordon tested positive for exogenous Testosterone and Clostebol, performance-enhancing substances, in violation of Major League Baseball's Joint Drug Prevention and Treatment Program. It is effective immediately. Gordon would be eligible to return on July 29 when the Marlins play host to the Cardinals. He would not be eligible to play in the postseason.

The announcement was made minutes after the Marlins defeated the Dodgers, 5-3, completing a four-game sweep at Dodger Stadium.

"Dee Gordon is a very important part of our team, and we all love him, and we support him," Marlins president David Samson said.

"That said, I do not like, or condone, what he did. He's an important member of this organization and will be for many years to come. It's a huge, huge disappointment. To the kids, to our fans, to his teammates, and to everyone in our organization who works hard every single day to put a product on the field and off the field that all Miamians will be proud of."

Gordon, an All-Star the past two seasons, won the NL batting title in 2015, when he posted a .333 average with a league-best 205 hits and 58 steals. He also led the NL with 64 steals in '14, before the Dodgers traded him to the Marlins.

"Though I did not do so knowingly, I have been informed that test results showed I ingested something that contained prohibited substances," Gordon said Friday morning in a statement released by the MLB Players Association. "The hardest part about this is feeling that I have let down my teammates, the organization, and the fans. I have been careful to avoid products that could contain something banned by MLB and the 20-plus tests that I have taken and passed throughout my career prove this. I made a mistake and I accept the consequences."

Gordon was off to a slower start this season, batting .266/.289/.340 with six steals through 21 games. However, his RBI single in the seventh inning on Thursday tied the score at 2-2 and knocked Dodgers starter Kenta Maeda out of the game. Gordon went 1-for-4 with a walk and run scored in Thursday's victory, Miami's fifth straight.

"Obviously, two different ends of the spectrum for us, and our team," manager Don Mattingly said. "You'd expect our team to be in there all excited, and then we get this news. Not quite the feeling, but from there, we'll support Dee. These guys love Dee, and I feel like he's one of our kids, to be honest with you. I love him, and then we're going to move forward."

Gordon, who turned 28 on April 22, is the son of former big league pitcher Tom Gordon and was a fourth-round pick by the Dodgers in the 2008 Draft. In 2015, he turned in one of the best individual seasons in Marlins history, and in January, they signed him to a new contract worth $50 million.

"He will be back 80 games from now, and he will be welcomed back to this organization," Samson said. "But in the interim period, we expect him, and we are positive that he will do whatever is necessary, to make it up to our fans, and to his teammates."

Samson said the Marlins were alerted on Thursday.

"The Marlins completely support the Major League Baseball Drug Prevention Program, in every way," Samson said. "That said, it's a huge disappointment and a huge loss for our team. Like I've said, we love Dee Gordon, but we do not like what he did."

At a time Miami is on a hot streak, the club now has to deal with some significant adversity, going without one of its leaders and top players until late July.

The Marlins will have to shuffle their roster a bit to fill in at second. Miguel Rojas is a candidate, as is Derek Dietrich. They even could use Martin Prado at second, from time to time, and go with Dietrich at third.

"I love Dee. We support him and I have nothing else to say," Prado said. "We had a great series and we played good baseball, the whole team. We have to continue to do that. We have a game tomorrow and we're going to play good baseball against a pretty good team and we want to keep that streak going."