NEW YORK — Alex Rodriguez's grievance hearing to overturn his 211-game suspension for alleged drug violations ended Thursday when both sides rested their cases, a day after the New York Yankees third baseman angrily walked out and decided not to testify in his own defense. Arbitrator Fredric Horowitz's decision on whether to uphold or alter the punishment for Rodriguez likely will be made in January, a person familiar with the proceedings told the Associated Press. The person spoke on condition of anonymity because no statements were authorized. Rodriguez's lawyers are already vowing to challenge the ruling in federal court, where judges usually are reticent to overturn an arbitration decision unless there is a finding the arbitrator was biased, exceeded his authority or failed to comply with the rules agreed to by the parties. The exact timing of a decision is uncertain. Baseball's Joint Drug Agreement states the arbitrator shall make “all reasonable efforts” to close the record in time to permit a decision within 25 days of the start of the hearing. But in this case, the hearing began Sept. 30, making that timetable impossible to meet. After the arbitrator renders his decision, the written opinion is to be issued within 30 days. It is unclear if Horowitz will issue his written opinion simultaneously with his decision. The timing of the case could complicate planning for the Yankees, who don't know if they will have to pay Rodriguez his $25 million salary and are unsure whether they will need a different starting third baseman. Rodriguez was suspended by Major League Baseball on Aug. 5 for alleged violations of baseball's drug policy and labor agreement stemming from the league's investigation of the Biogenesis of America anti-aging clinic in Florida. The players' association filed a grievance, and because Rodriguez was a first-time offender of the drug agreement, the suspension automatically was stayed pending a resolution of the grievance. Horowitz heard the case in a trio of four-day sessions, with management presenting its case from Sept. 30-Oct. 3 and Oct. 15-18. Rodriguez's side then took its turn during the first four days of this week. Rodriguez left in the middle of the 11th session Wednesday, furious the arbitrator refused to order MLB Commissioner Bud Selig to testify. Rodriguez and his lawyers then went on radio and television, accusing Selig of bias and the entire arbitration process of being flawed. — AP