Citing health issues for a key witness in the second bribery trial of former New York State Assembly Speaker Sheldon Silver, the judge presiding over the case has postponed the start of the trial by one week, to April 30.

U.S. District Judge Valerie Caproni of the Southern District of New York ruled that voir dire in Silver’s trial is still set to begin on April 16; at a pretrial conference on Tuesday, the judge said the trial is expected to last between four and six weeks.