A-Rod went public with his disenchantment.
"Obviously I'm very, very disappointed," he said. "I know I can help my team. Obviously, I'm frustrated but I agreed to this five-day plan, and on we go."
He repeatedly said he told the Yankees he was ready to return.
"Tomorrow night would be the perfect night to come back and get in the lineup," he said.
Whether he gets back on a big league field any time soon or ever plays for the Yankees again remains to be seen.
MLB has been investigating Rodriguez as part of its probe of the closed Biogenesis clinic in Florida accused in media reports of distributing banned performance-enhancing drugs. A suspension appears likely, but Rodriguez could ask the players' association to contest a drug penalty — making it possible he might not have to serve any time until next year.
He is among the dozen or so players under investigation by MLB; he has said in the past that he used PEDs from 2001-03 while with Texas but maintained he has not used them since.
The Yankees intend to discipline A-Rod for seeking a second medical opinion without their permission, a person familiar with the team's deliberations said.
The exact penalty had not been determined, the person said, speaking on condition of anonymity to The Associated Press because no statements were authorized. A fine appeared to be the most likely option.
Meantime, Rodriguez's return from hip surgery has created more drama than most players experience in their entire careers.
Seemingly days away from rejoining the Yankees, Rodriguez injured a leg last weekend and was sent to New York for an MRI on Sunday. Team physician Dr. Christopher Ahmad diagnosed a grade 1 strain, the least severe level.