ALBANY  Gov. David A. Paterson, after a confusing and even embarrassing two-month ordeal, said Thursday that he would announce a replacement to fill Hillary Rodham Clinton’s Senate seat at noon on Friday.

Mr. Paterson made the announcement after a day of anonymous and often bitter sniping over Caroline Kennedy’s mystifying departure from the Senate field, which, after several twists and turns, was announced shortly after midnight on Thursday.

Because the governor has often contradicted his own comments about the Senate pick in the course of a single day, no one in the capital appeared ready to say for certain who the new senator would be. But among lawmakers, Democratic operatives and even some of the governor’s advisers, the name most frequently mentioned as the likely pick was Representative Kirsten E. Gillibrand, though other candidates, including Randi Weingarten, the president of the American Federation of Teachers, were not ruled out.

But if Mr. Paterson is hoping to quiet the tumult by picking Ms. Gillibrand, there are already indications he may not get his wish. Ms. Gillibrand, a centrist Democrat from upstate who has been endorsed by the National Rifle Association, is controversial among some of the party’s more liberal leaders downstate.