PROVIDENCE — Opening arguments are scheduled today in the federal corruption trial of two former CVS executives accused of bribing a Rhode Island state senator.

John R. Kramer, 75, and Carlos Ortiz, 64, are charged with bribery and conspiracy to deprive Rhode Islanders of the honest services of a public official, former Sen. John A. Celona, of North Providence.

Last week, the prosecution and the defense chose a jury of 12 members, plus four alternates, to hear evidence in the trial, which is expected to last four weeks. Chief U.S. District Judge Mary M. Lisi has scheduled testimony from 9 a.m. to 1 p.m. at the downtown federal courthouse in Providence, leaving the afternoons free for any issues that the lawyers need to argue outside the presence of the jury.

After both sides present their opening arguments to the jury, the first witness will take the stand. While the leadoff witness was not announced, the prosecution’s featured witness, Celona, is sitting in a jail cell at the Wyatt Detention Center, in Central Falls, having been moved there last week from a federal prison in Pennsylvania.

Celona, who is serving a 2½-year sentence, pleaded guilty to selling his office to CVS, Roger Williams Medical Center and Blue Cross & Blue Shield of Rhode Island, and has cooperated with authorities in the wide-ranging State House corruption probe known as Operation Dollar Bill.

The CVS charges revolve around Celona’s hiring as a $1,000-a-month consultant by the nation’s biggest drugstore chain, ostensibly to help with community relations, but in reality to do the company’s bidding at the State House, prosecutors charge.

One of the issues that has surfaced in pretrial skirmishes between the prosecution and the defense is the government’s proposed use of state grand-jury testimony by Ortiz suggesting that Ortiz was not enthusiastic about Celona’s hiring, and that it was more the decision of Kramer, Ortiz’s superior. Kramer’s lawyers object, saying that they would have no way to cross-examine Ortiz unless he takes the stand in his defense.

mstanton@projo.com