New York Yankees third baseman Alex Rodriguez, the highest paid player in baseball, has been banned for 211 games, starting on Thursday and covering the remainder of this season and all of next, for violations of Major League Baseball's joint drug prevention and treatment program and its basic agreement.

In a statement tonight, the league said the 38-year-old was being punished for "his use and possession of numerous forms of prohibited performance-enhancing substances, including testosterone and human growth hormone, over the course of multiple years" and for his attempts to cover up those violations and obstruct a league investigation.

Rodriguez, who had been hoping to make his 2013 season debut tonight has appealed the ruling and his case will be heard by arbitrator Frederic Horowitz, most likely within three weeks, MLB confirmed on its website. He is free to play while the appeal progresses.

Rodriguez has the backing of the Major League Baseball Players Association, whose executive director Michael Weiner released a statement following today's announcements saying: "The accepted suspensions announced today are consistent with the punishments set forth in the Joint Drug Agreement, and were arrived at only after hours of intense negotiations between the bargaining parties, the players and their representatives.

"For the player appealing, Alex Rodriguez, we agree with his decision to fight his suspension. We believe that the Commissioner has not acted appropriately under the Basic Agreement. Mr Rodriguez knows that the Union, consistent with its history, will defend his rights vigorously.

"The Union's members have made it clear that they want a clean game. They support efforts to discipline players, and harshly, to help ensure an even playing field for all. The players support the Union's efforts to uphold the JDA while at the same time guaranteeing that players receive the due process rights and confidentiality protections granted under the agreement."