Raducanu withdrew from the British team for next week’s Finals at the end of last week after testing her right wrist on court.
The 19-year-old was also forced out of last month’s Transylvania Open in Romania with the same injury.
“Right now, from what I understand, it’s something she will recover from – and she’s confident of that,” Keothavong told BBC Sport.
She just needs a bit more time and Billie Jean King Cup is too soon.
“Wrist injuries are never easy, but I think this one is under control. She’s got good people around her, and she’s used her time to really work on other areas of her fitness.”
Radcuanu is currently working with Andy Murray’s former physical trainer Jez Green at the National Tennis Centre in Roehampton.
Her next target is a pre-season exhibition in Abu Dhabi on 16 December.
“She’s been putting the hours in – she’s looking super fit,” added Keothavong.
“She’s been putting a lot of physical effort in in the gym, and I think she will be a stronger player come next year.
“She did everything she could have done to be fit, but it just wasn’t going to happen.
“She went to the court and tried hitting a few balls, but it wasn’t ideal and she just needs more time.”
Keothavong has named the fourth and fifth members of her team for the finals in Glasgow.
