Sri Lanka have made sweeping changes to the squad which drew the preceding two-Test series 1-1 with their hosts, and seven new players have been included to boost their stocks.
"There are a lot of youngsters, and what we are trying to do is develop a team for the next World Cup," Sri Lanka captain Mahela Jayawardene said.
"We are going to try a few guys, some exciting youngsters. We want to be competitive against West Indies and see where we are in terms of our preparation for the World Cup.
"It's going to be a very good series because West Indies are a very good one-day unit as well."
Joining the squad for the ODI series are openers Upul Tharanga and Chamara Kapugedera, batsmen Ajantha Mendis, Mahela Udawatte, and Jehan Mubarak, all-rounder Kaushalya Weeraratne, and leg-spinner Malinga Bandara.
They have replaced Michael Vandort, Malinda Warnapura, Thilan Samaraweera, Prasanna Jayawardene, Muttiah Muralitharan, Ishara Amerasinge, and Chanaka Welegedara.
"Test cricket and ODI cricket are totally different, and you need to totally focus yourself on the ODIs differently," Jayawardene said.
"We've got new guys coming into the set-up. Our challenge is to try and blend quickly as possible, get them going and play some good cricket. We're looking forward to it."
Sri Lanka will jointly host the 2011 World Cup with India, Pakistan, and Bangladesh, and Jayawardene disclosed that his side is again setting itself the goal of reaching the Final as they did in the 2007 version in the Caribbean where they lost to three-time defending champions Australia.
"Cricket is going to go on, and players will come and go," he said. "We just need to make sure we have the right combinations going.
"It is just two-and-a-half years away from the World Cup. We need to make sure we get the personnel right and give opportunities.
"If you are going to bring youngsters in, those guys need to play at least 40 or 50 ODIs before the World Cup."
West Indies appear to have a similar, but less publicised policy, when they announced a 16-member squad.
Off-spin bowler Amit Jaggernauth is the only casualty from the 13-member squad picked for the second Test which ended on Sunday with a six-wicket victory for the home team, and four players have been added to bolster the squad.
Coming into the side are wicketkeeper/batsman Patrick Browne, Runako Morton, Kieron Pollard, and all-rounder Darren Sammy.
Browne played a couple impressive innings when he made his ODI debut in South Africa, and Morton has scored heavily in the domestic first-class competition since his return from South Africa and was still overlooked for the Test series.
Pollard was a contentious choice for the World Cup side last year and then was strangely ignored, and the hardworking Sammy too, has been treated harshly when he was overlooked for the Tests against the Sri Lankans, although he has hardly placed a foot wrong since his Test debut.
The second ODI will be played on Saturday, also at Queen's Park Oval, and the final match will be a day/night contest next Tuesday, April 15, at the Beausejour Stadium in St. Lucia.
West Indies (from): Chris Gayle (capt), Ramnaresh Sarwan (vice-capt), Sulieman Benn, Patrick Browne, Dwayne Bravo, Shivnarine Chanderpaul, Sewnarine Chattergoon, Fidel Edwards, Runako Morton, Keiron Pollard, Daren Powell, Denesh Ramdin, Darren Sammy, Marlon Samuels, Devon Smith, Jerome Taylor
Sri Lanka (from): Mahela Jaywardene (capt), Kumar Sangakkara (vice-capt), Malinga Bandara, Tillakeratne Dilshan, Rangana Herath, Chamara Kapugedera, Nuwan Kulasekera, Ajantha Mendis, Jehan Mubarak, Chamara Silva, Upul Tharanga, Thilan Thushara, Mahela Udawatte, Chaminda Vaas, Kaushalya Weeraratne,.