Although her list is not limited to those two, Clinton has spoken highly of both in recent days to friends and advisers as she closes in on an announcement that one aide told CNN is likely to come Friday.

Among those from whom Clinton has received advice is President Obama, who has offered thoughts on the two contenders who serve on his Cabinet, Vilsack and Labor Secretary Thomas E. Perez, several Democrats said. These individuals did not say what advice the president gave.

These and other Democrats cautioned that Clinton has not made a final choice and is keeping mum about her deliberations. Several other people remain in the running, they said. Clinton campaign press secretary Brian Fallon declined to comment.

Clinton is expected to campaign alongside her running mate on Friday or Saturday in Florida, three Democrats familiar with aspects of the plan said. The campaign has announced only that she will make stops in several Florida cities over those two days, in the runup to her party’s national convention. The convention, where Clinton will formally claim the nomination as the first woman to head a major-party ticket, begins Monday in Philadelphia.