(CNN) Joe Biden has indicated it is "all but certain" he'll run in 2020, Sen. Chris Coons said Wednesday.

"I'm optimistic he's going to run for president. I'm actually confident he's going to run for president. He's 95% there and everything that needs to be in place for him to have a strong and successful launch is being put together," Coons, a Delaware Democrat who is one of Biden's closest allies, told CNN's John Berman on "New Day."

"I understand why he hasn't yet made the final decision," Coons said. "This is something he and Jill need some time to reflect on and pray on."

Biden teased a possible run Tuesday when he told a group of applauding supporters at a firefighters conference, "I appreciate the energy you showed when I got up here. Save it a little longer, I may need it in a few weeks."

Coons said Wednesday, "He's told me that he is all but certain he is going to run. He hasn't made that last decision."

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