First-team manager Adrian Birrell believes Hampshire can fight for honours this season, whether or not they sign a replacement for Dimuth Karunaratne.
The opener signed for Hampshire last month after leading Sri Lanka to a surprise Test series victory over South Africa as stand-in skipper.
He is now being considered for the captain's role at the World Cup.
Birrell told BBC Radio Solent that the club are seeking a replacement.
"There is some activity behind the scenes and there are some players out there, but there are a lot of unknowns because no one has selected their World Cup squad yet, so we've got to work with some players who aren't in contention," he said.
Karunaratne has been asked to remain in Sri Lanka to play in their domestic 50-over competition, before the World Cup begins in May.
"We have lost a quality individual with a lot of fight and determination," added Birrell. "These are all the qualities we need in our setup to play four-day cricket, so it is a bit of a blow, but we will probably sign another professional in his place.
"Having said that, we have a good squad of players here and part of me is saying that we can fight without a replacement. I have full faith in the players we have and if we do get someone in then it's a bit of a bonus."
Former Ireland coach Birrell, who has replaced former England all-rounder Craig White at Hampshire, was full of praise for the 30-year-old after his exploits in South Africa.
He said: "He did fantastically well with Sri Lanka. You would have got good odds on Sri Lanka beating South Africa and he was the captain.
"You've got to doff your cap to him for what he has achieved with his team and it is just wonderful to see.
"It is great for cricket and by all accounts he is going to be in the World Cup so we wish him well and just say a massive congratulations."
Hampshire began a two-day friendly against Middlesex at the Ageas Bowl on Thursday, while their opening County Championship Division One fixture is at home to Essex on Friday, 5 April.