"Most losing presidential candidates never totally close the doors to running for president," Zeleny said.
"But I think we have to at least leave our mind open to the possibility that she is still talking about it.
"She wants to take on Trump. Could she win a Democratic primary to do it? I don't know the answer to that."
On Saturday night, President Donald Trump tweeted about both Hillary and Roger Stone.
He wrote: "CBS reports that in the Roger Stone indictment, data was 'released during the 2016 Election to damage Hillary Clinton.' Oh really! What about the Fake and Unverified 'Dossier,' a total phony conjob, that was paid for by Crooked Hillary to damage me and the Trump Campaign?
"What about all of the one sided Fake Media coverage (collusion with Crooked H?) that I had to endure during my very successful presidential campaign.
"What about the now revealed bias by Facebook and many others. Roger Stone didn't even work for me anywhere near the Election!"
He then wrote: "WITCH HUNT".
Stone, a Trump ally and a longtime Republican operative, did not rule out on Sunday cooperating with Special Counsel Robert Mueller in his investigation of Russian meddling in the 2016 US presidential election.
If Clinton does decide to throw her hat in the ring one more time, she would need to emerge from a large and formidable pool of Democrats who have either announced they are running or are on the verge of doing so.
US Senators Elizabeth Warren, Kamal Harris and Kirsten Gillibrand are in the race, and more senators are weighing bids.