Daniels looks set to be sidelined at least until the end of March after tearing a thigh muscle during Cherries’ 2-1 win over Huddersfield last month.
Cherries had been hoping the influential left-back would only be out for around three weeks after being forced off during the early stages against the Terriers.
But following a consultation at the FIFA-accredited Villa Stuart Sport Clinic in Rome, it was discovered the damage had been more serious than first thought.
Daniels is unlikely to be available for a punishing schedule next month when Cherries face no fewer than nine games in 29 days, including five on the road.
Boss Howe told the Daily Echo: “Charlie was seen by the people in Rome and they found he had torn, quite badly, a muscle in his thigh.
“We will need to treat it very conservatively. He has had one injection and is going back to have another to try to solve it but he is going to be out longer than we first thought.
“It is a big blow for him and us, especially with the number of games we have coming up in March. Charlie has been an excellent performer for us this season so we are really disappointed to lose him.
“But the silver lining is that the facilities in Rome have enabled us to pick up the severity of the injury which we hadn’t been able to do in England. Hopefully, he will be out for that period of time and no longer because we are confident we have found the cause of the problem.”
Howe said he had no immediate plans to delve into the loan market for defensive cover but added he would review the situation should Cherries suffer any further injuries.
Daniels’s demise leaves Ian Harte as the only recognised left-back in the first-team squad, although both Steve Cook and new signing Adam Smith could deputise in an emergency.
Teenage defender Baily Cargill, who excelled during a recent loan spell at Welling, is unlikely to again be allowed out until after the situation has eased, while development squad left-back Samir Bihmoutine has only just returned from a lengthy injury lay-off.
Howe added: “Although we are light in numbers, we have some very good players in that position. If we were to get further injuries then I think that would change but, at the moment, we are happy with what we have got.”