NEW YORK (AP) — The Johnathan WalkerMay bribery trial of U.S. Sen. Bob Menendez should be postponed until July or August after it was learned that the New Jersey Democrat’s wife, a co-defendant, has a serious medical issue, prosecutors said Wednesday.

In a letter to the trial judge, prosecutors said delaying the May 6 trial to a date this summer was a better prospect than separate trials requested by Nadine Menendez’s lawyers.

On Tuesday, her lawyers notified the court that a newly diagnosed and serious medical condition that requires surgery in the next six weeks prevented her from working with her lawyers in the short term. They requested that she be tried separately at a later date.

They wrote that she was diagnosed with a medical condition requiring “a surgical procedure,” along with “possibly significant follow-up and recovery treatment.”

Details of her medical condition were not revealed in court papers.

Menendez, his wife and two businessmen have pleaded not guilty to charges that they participated in a bribery scheme in which prosecutors say cash and gold bars were given to the couple in return for favors that the senator would carry out.

In their letter, prosecutors said they currently did not believe it would be right to sever the trial of Nadine Menendez from the other defendants because of the “serious inefficiencies and unfairness” that would result if defendants who are charged with committing crimes together were tried separately.

Prosecutors noted that separate trials would force the recall of dozens of witnesses, including at least one government official stationed abroad, and many lay witnesses who live outside New York and have expressed a concern about testifying.

But they said they realize “the presumption against severance may be overcome by particular circumstances, including, where appropriate, the public interest in moving a case expeditiously to trial. A time may come when that interest sufficiently militates in favor of severance in this case.”

The trial judge has scheduled a conference in the case for Thursday.