The 34-page decision written by arbitrator Fredric Horowitz became a matter of public record after lawyers for Rodriguez asked a federal judge on Monday to throw out his ruling, charging he had exhibited "blatant partiality" toward MLB.
The decision revealed the first glimpse of a proceeding that took place behind closed doors, and resulted in Horowitz lowering MLB's initial 211-game suspension announced last August to 162 games covering the 2014 season and any postseason games.
It was the longest ever doping ban for a player, and came down even though New York Yankees slugger Rodriguez, who stands to lose $25 million in salary, had not failed a drug test.
"While this length of suspension may be unprecedented for a MLB player, so is the misconduct he committed," Horowitz wrote in his conclusion.
Horowitz found that Rodriguez used testosterone, hGH and IGF-1, all performance enhancing substances (PES) banned by MLB, over a three-year period, and had obstructed the MLB probe that also led to the suspension of 13 other players.
The ruling was based on a mountain of evidence provided by the lynchpin of the doping operation, Anthony Bosch, the owner of a now-shuttered Florida anti-aging clinic called Biogenesis. Yet despite arguments by Rodriguez lawyers that Bosch's evidence was not trustworthy, Horowitz was convinced.
"Contrary to the claim of Rodriguez, the challenges lodged to the credibility of Bosch's testimony do not effectively refute or undermine the findings of JDA (Joint Drug Agreement) violations," Horowitz wrote, citing a proponderence of evidence.
The testimony of Bosch under oath was "direct, credible and squarely corroborated by excerpts from several of the hundreds of pages of his personal composition notebooks ... (and) in the evidence of BlackBerry exchanges between Rodriguez and Bosch."
The arbitrator said evidence showed Bosch first met up with Rodriguez in July 2010 through his cousin, Yuri Sucart, and that the player began a long association with the PES dealer.
They exchanged 556 text messages in 2012 alone and met numerous times, including once in a Starbucks bathroom in Miami, he said.
Horowitz said evidence showed that Bosch rode up service elevators to meet with Rodriguez at the Yankees team hotel in Atlanta, met him at the player's Miami home and New York apartment and used code names in text messages for the banned substances in giving dosage advice.
The arbitrator wrote that in the depths of a horrid batting slump during the American League Championship Series in October 2012, Rodriguez summoned Bosch to Detroit for a new supply.
MLB paid $125,000 for copies of documents, which Rodriguez's side claimed was improper conduct in their probe, but Horowitz pointed out in his decision that Rodriguez had also made payments to procure and destroy evidence related to the case.
Horowitz also dismissed an "indiscreet sexual liaison" between an MLB investigator and a former Biogenesis employee, saying it yielded no relevant information for the case.
Two other key arguments made by the Rodriguez side were deflected by Horowitz.
Rodriguez had argued that since he had not tested positive for any drugs, that science was on his side in his claim of innocence.
"The claim by Rodriguez that science exonerates him in this case is not supported by any evidence in this record. It is recognized Rodriguez passed eleven drug tests administered by MLB from 2010 through 2012.
"The assertion that Rodriguez would have failed those tests had he consumed those PES as alleged is not persuasive. As advanced as MLB's program has become, no drug testing program will catch every player."
Rodriguez had also argued that he had been singled out for severe punishment, since 12 other players had received 50-game suspensions, as specified in the JDA for a first offense, while former National League most valuable player Ryan Braun accepted a 65-game suspension.
The 38-year-old third baseman, popularly known as A-Rod, is currently fifth on baseball's all-time home run list with 654 and was once widely expected to challenge Barry Bonds' record of 762 home runs. Bonds was also repeatedly linked to doping.
"A review of all the evidence and argument presented by all parties in this proceeding clearly and convincingly establishes Rodriguez committed multiple violations," wrote Horowitz, "(and) used and/or possessed three discrete PES banned ... during the three-year period."