Jay Reisinger, a lawyer who has represented Rodriguez in recent years, said the three-time AL MVP had retained Roy Black, an attorney from Rodriguez's hometown of Miami. Black's clients have included Rush Limbaugh and William Kennedy Smith.
Bosch did not return a phone message seeking comment.
MLB hopes to gain the cooperation of Bosch and others connected with the clinic, another baseball official said, also on condition of anonymity because no public statements on the matter were authorized. In order to successfully discipline players based on the records, witnesses would be needed to authenticate them, the official said.
Players could be asked to appear before MLB for interviews, but the official said MLB would be reluctant to request interviews before it has more evidence.
Rodriguez spent years denying he used PEDs before Sports Illustrated reported in February 2009 that he tested positive for two steroids in MLB's anonymous survey while with the Texas Rangers in 2003. Two days later, he admitted in an ESPN interview that he used PEDs over a three-year period. He has denied using PEDs after 2003.
If the new allegations were true, the Yankees would face high hurdles to get out of the final five years and $114 million of Rodriguez's record $275 million, 10-year contract. Because management and the players' union have a joint drug agreement, an arbitrator could determine that any action taken by the team amounted to multiple punishments for the same offense.
But if Rodriguez were to end his career because of the injury, about 85 percent of the money owed by the Yankees would be covered by insurance, one of the baseball officials said.
Gonzalez, 21-8 for the Washington Nationals last season, posted on his Twitter feed: "I've never used performance enhancing drugs of any kind and I never will, I've never met or spoken with tony Bosch or used any substance provided by him. anything said to the contrary is a lie."
Colon was not issuing a statement, agent Adam Katz said through spokeswoman Lisa Cohen.
"We are aware of certain allegations and inferences," Cruz's law firm, Farrell & Reisinger, said in a statement. "To the extent these allegations and inferences refer to Nelson, they are denied."
Cruz and Gonzalez had not previously been linked to performance-enhancing drugs. Cruz hit 24 home runs last year for the Rangers.
The New Times report said it obtained notes by Bosch listing the players' names and the substances they received. Several unidentified employees and clients confirmed to the publication that the clinic distributed the substances, the paper said. The employees said that Bosch bragged of supplying drugs to professional athletes but that they never saw the sports stars in the office.
The paper said the records list that Rodriguez paid for HGH; testosterone cream; IGF-1, a substance banned by baseball that stimulates insulin production; and GHRP, which releases growth hormones.
Associated Press writers Jennifer Kay in Coral Gables, Fla., and Curt Anderson in Miami, and AP Sports Writers Howard Fendrich and Tim Reynolds contributed to this report.