People familiar with the case told The Associated Press on Friday that arbitrator Fredric Horowitz could issue his decision this weekend. The people spoke on condition of anonymity because no statements were authorized.
The New York Yankees third baseman, a three-time AL MVP, was suspended for 211 games on Aug. 5 by baseball Commissioner Bud Selig. The penalty was given for alleged violations of the sport's drug agreement and labour contract and followed Major League Baseball's investigation of the Biogenesis of America anti-aging clinic, which was accused of distributing banned performance-enhancing drugs.
The Major League Baseball Players Association filed a grievance saying the discipline was without "just cause."
Horowitz, MLB's independent arbitrator, heard the case over 12 sessions from Sept. 30 until Nov. 20. The sides submitted briefs last month.
Rodriguez's lawyers have threatened to go to federal court in an attempt to overturn a decision not to their liking. The Supreme Court has given judges little leeway to alter arbitrator's rulings.