National League MVP Ryan Braun, who last season led the Milwaukee Brewers to their first division title in nearly three decades, has tested positive for a performance-enhancing drug and faces a 50-game suspension if the initial finding is upheld, two sources familiar with the case told "Outside the Lines."

Major League Baseball has not announced the positive test because Braun is disputing the result through arbitration.

A spokesman for Braun confirmed the positive test Saturday and issued a statement: "There are highly unusual circumstances surrounding this case which will support Ryan's complete innocence and demonstrate there was absolutely no intentional violation of the program. While Ryan has impeccable character and no previous history, unfortunately, because of the process we have to maintain confidentiality and are not able to discuss it any further, but we are confident he will ultimately be exonerated."

USA Today reported Saturday night that Braun said of the test result: "It's B.S."

The 28-year-old Braun had to provide a urine sample for testing during the playoffs, and he was notified of the positive test sometime in late October -- about a month before he was named the National League's most valuable player.

The Baseball Writers Association of America, who votes on the award, will not strip Braun of his MVP if he gets suspended.

"I got the same question after Ken Caminiti came clean about his steroids usage, and whether we should give the 1996 MVP award instead to (second-place finisher) Mike Piazza," BBWAA secretary-treasurer Jack O'Connell told The Los Angeles Times. "The answer is no."

The positive result was triggered by elevated levels of testosterone in Braun's system, the sources told "Outside the Lines." A subsequent, more comprehensive test revealed the testosterone was synthetic -- not produced by Braun's body.

Every individual naturally produces testosterone and a substance called epitestosterone, typically at a ratio of 1-to-1. In Major League Baseball, if the ratio comes in at 4-to-1 or higher during testing, a player is deemed to have tested positive. The sources did not indicate how high above the threshold Braun's sample tested.

To affirm the results and strengthen its case, MLB asked the World Anti-Doping Agency lab in Montreal, which conducts its testing, to perform a secondary test to determine whether the testosterone spike resulted from natural variations within Braun's body or from an artificial source. The test indicated the testosterone was exogenous, meaning it came from outside his body.

The Brewers said the team had not been contacted by the commissioner's office and the team had no knowledge of a failed test.

"Ryan Braun has been a model citizen in every sense of the word, both in the Milwaukee community and for the Brewers," Brewers owner Mark Attanasio said in a statement released Saturday night. "Since joining our organization in 2005, he has been a person of character and integrity."

Messages left for MLB officials were not returned. Greg Bouris, spokesman for the Major League Baseball Players Association, declined comment.

"We are dealing with an incomplete set of facts and speculation," Attanasio said in the news release. "Before there is a rush to judgment, Ryan deserves the right to be heard. We are committed to supporting Ryan to get to the truth of what happened in this unfortunate situation."

Since being informed of the results, Braun has been disputing his case. A source close to Braun said that when he was told about the positive test, he immediately requested to be tested again. That second test, using a different sample that was tested by Braun's camp, the source said, was not positive. Those close to Braun believe that the difference between the two tests will show that the first test was invalid. Although Braun's representatives acknowledge that a non-positive test would not negate a positive one, they believe the second test shows certain anomalies that will suggest problems with the first. They declined to specify.

Milwaukee Brewers' Ryan Braun carried the team to its first division title in nearly three decades last season, leading the league in slugging percentage at .597, with a .332 batting average, 33 home runs and 111 runs batted in. AP Photo/Jeff Roberson

The outfielder has told those around him that he did not knowingly take any banned substances and hoped to prove that during the arbitration process. No major league player has ever successfully appealed a positive test.

MLB's Joint Drug Prevention and Treatment Policy calls for strict liability among players, meaning if a player tests positive, the league is "not required to otherwise establish intent, fault, negligence or knowing use of a Prohibited Substance on the Player's part to establish such a violation."

Even if a player can establish he did not knowingly take a banned substance, he must show he was not in any way negligent to appeal successfully. For example, taking a dietary supplement that contains an unlabeled performance-enhancing drug would not be sufficient grounds for appeal, but if he were to show that he ingested something that was either tampered with or no player reasonably could have assumed to have been contaminated, the appeal might succeed.

The source close to Braun said he believes that standard can be met.

Once criticized for protecting its biggest stars from scandal, the league is now faced with the possibility of suspending one of the game's best and most-admired players.

Braun had never been linked to PEDs previously; in fact, at the 2009 All-Star Game in St. Louis, when commissioner Bud Selig addressed efforts by Albert Pujols to tamp down questions about steroid use, he invoked Braun as a shining example of the sport's tough testing policy.

"Albert Pujols is absolutely right. He has been tested since he started playing," Selig said. "So has Ryan Howard. So has Ryan Braun, Ryan Zimmerman. Since they were in the minors."

About a month before that, Selig was quoted in The Arizona Republic as saying, "Our minor league testing program is in its ninth year, and that means all the great young players in baseball, from Ryan Howard to Ryan Braun, have all been tested for nine years. There's a system in place, and it's working. We know we have the toughest testing program in major league sports."

Earlier that spring, after Alex Rodriguez was exposed for using steroids, Braun spoke to MLB.com about the "mistakes" made by the superstar. Braun said he met Rodriguez in 2001 during a recruiting trip to the University of Miami.

Asked if he were surprised that Rodriguez had been exposed as a steroid user, Braun was quoted saying, "I don't know if I would say I was surprised. I feel like it was so rampant, so prevalent, in baseball during that time period that not much surprises me anymore. If anything, I was surprised he got caught, that it came out this long after he supposedly did it."

On whether he had ever been tempted to try performance-enhancing drugs, Braun said, "It's never something that I sought."

MLB.com wrote that Braun then showed "a flash of his sense of humor and his well-documented self-confidence" by adding, "I would never do it because if I took steroids, I would hit 60 or 70 home runs."

Braun was speaking to the website prior to the news conference at which Rodriguez admitted his use.

"... The best thing he can do is come out, admit to everything and be completely honest," Braun said. "The situation will die a lot faster if he tells the whole truth."

Since breaking into the majors in 2007 at 23, Braun has emerged as one of the sport's top young players. He won the NL Rookie of the Year in 2007 and was an All-Star each of the past four seasons.

In his rookie season, Braun hit 34 homers and drove in 97 runs, while amassing a .634 slugging percentage in just 113 games. He had 37 home runs and 106 RBIs the following year, then saw his power numbers decline modestly over the next two seasons. He still hit 25 home run runs and had a .501 slugging percentage in 2010.

In April, Braun signed a five-year contract extension worth $105 million. He then went out and had his best season ever, carrying the Brewers to their first division title in nearly three decades. He led the league in slugging percentage at .597, with a .332 batting average, 33 home runs, 111 runs batted in, 109 runs scored and 33 stolen bases.

Braun turned 28 on Nov. 17 and five days later was named the NL MVP. Now, though, he's looking at a 50-game suspension to open the 2012 season, and, of course, all sorts of questions about what role steroids have played in his success.

Mark Fainaru-Wada and T.J. Quinn are investigative reporters with ESPN's enterprise unit. Fainaru-Wada can be reached at markfwespn@gmail.com. Quinn can be reached at tjquinn31@yahoo.com.