(CNN) -- Milwaukee Brewers outfielder Ryan Braun blasted Major League Baseball's drug testing system Friday, one day after an arbitration board tossed out a 50-game suspension imposed as the result of drug tests conducted last year.
This is a process where players are "100% guilty until proven innocent," and in this case it "was fatally flawed," Braun said. "We won because the truth is on my side."
Major League Baseball Executive Vice President for Labor Relations Rob Manfred roundly rejected the player's accusations, though he said some changes would be made to "clarify" the process.
"Major League Baseball runs the highest quality drug testing program of any professional sports organization in the world ... Our program is not 'fatally flawed.' Changes will be made promptly to clarify the instructions provided to collectors regarding when samples should be delivered to FedEx based on the arbitrator's decision," he wrote in a statement.
Braun, the 2011 National League MVP, told reporters that nearly two days passed between when a collector took his sample and when it was delivered to a FedEx office.
"What could have possibly happened to it during that 44-hour period? There were a lot of things that we learned about the collector, about the collection process, about the way that the entire thing worked that made us very concerned and very suspicious about what could have actually happened," Braun said.
My name's been "dragged through the mud," he told reporters. Countless "inaccurate, erroneous, and completely fabricated stories" have been circulated, and the league's response has been "a little bit sad and disappointing."
He said he is still considering all possible legal options.
Thursday's decision marked the first successful appeal of a suspension under Major League Baseball's anti-drug policy. Braun hailed it as "the the first step in restoring my good name and reputation," but the league said it "vehemently disagrees" with the ruling.
Manfred defended the collector involved in Braun's case, saying the person "acted in a professional and appropriate manner."
The 28-year-old Braun led the Brewers to the team's first division title in three decades in 2011, with a .332 batting average, 33 home runs and 111 runs batted in. He was slapped with the suspension in December after a drug test that the sports network ESPN, citing unidentified sources, said showed high levels of testosterone.
Braun said at the time there were "highly unusual circumstances" that would show his innocence. The arbitration panel apparently agreed, voting 2-1 to overturn the suspension, according to the MLB Players Association.
In a brief statement, the players' union said the result would not be made public normally -- but all parties agreed to release the decision "given the particulars of this case."
Baseball officials have said drug testing is "essential to the integrity of our game," and that they "will exhaust all avenues in pursuit of the appropriate discipline" when a player tests positive for banned substances.
A third-party review is part of the process, Manfred said in an earlier statement on the Braun decision, and the leagues "have always respected that process."
However, he added, "Major League Baseball vehemently disagrees with the decision rendered" by the panel, led by arbitrator Shyam Das.
CNN's Alan Silverleib and David Close contributed to this report