The tone was in sharp contrast to Rodriguez, who was upset that independent arbitrator Fredric Horowitz declined to call Commissioner Bud Selig to testify.
There is no precedent for Selig to appear at such a hearing, however.
"In the entire history of the Joint Drug Agreement, the Commissioner has not testified in a single case," MLB said in a second statement. "Major League Baseball has the burden of proof in this matter. MLB selected Rob Manfred as its witness to explain the penalty imposed in this case. Mr. Rodriguez and the Players Association have no right to dictate how Baseball's case is to proceed any more than Baseball has the right to dictate how their case proceeds. Today's antics are an obvious attempt to justify Mr. Rodriguez's continuing refusal to testify under oath."
Shortly after Rodriguez walked out of MLB's Park Avenue offices in New York, a statement was released through one of his publicists.
"I am disgusted with this abusive process, designed to ensure that the player fails," Rodriguez said. "I have sat through 10 days of testimony by felons and liars, sitting quietly through every minute, trying to respect the league and the process. This morning, after Bud Selig refused to come in and testify about his rationale for the unprecedented and totally baseless punishment he hit me with, the arbitrator selected by MLB and the Players Association refused to order Selig to come in and face me."
Rodriguez then appeared on WFAN with host Mike Francesa, who asked multiple times whether Rodriguez was guilty of any of the actions he is being accused of. Rodriguez, accompanied by one of his lawyers, repeatedly and unequivocally denied any guilt.
The Players Association also released a statement late Wednesday afternoon.
"The MLBPA believes that every player has the right under our arbitration process to directly confront his accuser. We argued strenuously to the Arbitrator in Alex's case that the Commissioner should be required to appear and testify. While we respectfully disagree with the Arbitrator's ruling, we will abide by it as we continue to vigorously challenge Alex's suspension within the context of this hearing."
After Rodriguez left -- he slammed his fists on the table and cursed at MLB chief operating officer Rob Manfred before departing -- his attorneys remained in the building until about 1:30 p.m. While Rodriguez does not have to be present for the hearings to continue, unless he returns he obviously will be unable to testify in his own behalf.
Rodriguez is one of 13 players connected to the Biogenesis scandal to be disciplined by MLB. The other players, who were suspended between 50 and 65 games, did not appeal. It remains unclear whether Wednesday's events will impact the timing of Horowitz's decision, which had been expected sometime next month.
Paul Hagen is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.