The news comes after Rodriguez filed suit against the MLBPA and MLB in an attempt to overturn his 162-game suspension for his violation of the league's performance-enhancing drug policy.
Rodriguez's legal team contends that the union was in breach of its duty and failed to properly represent him in his appeal of his original 211-game suspension.
"It is unfortunate that Alex Rodriguez has chosen to sue the Players Association," said Tony Clark, head of the union, in the report. "His claim is completely without merit and we will aggressively defend ourselves and our members from these baseless charges. The Players Association has vigorously defended Mr. Rodriguez's rights throughout the Biogenesis investigation, and indeed throughout his career. Mr. Rodriguez's allegation that the association has failed to fairly represent him is outrageous, and his gratuitous attacks on our former executive director, Michael Weiner, are inexcusable. When all is said and done, I am confident the Players Association will prevail."
Despite missing out on most of his salary this coming season because of the suspension, Rodriguez is still owed $61 million on a contract that runs through 2017 with the Yankees.