Great Britain women’s captain Alex Danson has been left out of the squad for the inaugural FIH Pro League as she continues her recovery from concussion.
The 33-year-old missed the Champions Trophy in November after banging her head on a concrete chair on holiday.
She can be added at a later date for the tournament, which takes place between January and June.
Barry Middleton is not included in the men’s squad as he takes a break from international hockey.
The 34-year-old has 432 combined caps for Great Britain and England following his fourth World Cup earlier this month, in which England finished fourth after being thrashed by Australia in the third-place play-off.
The Pro League sees nine teams in each of the men’s and women’s events face each other home and away, with the top four teams advancing to a grand final in Amstelveen in the Netherlands.
The competition, set up by the International Hockey Federation (FIH), replaces the Hockey World League and serves as qualification for the World Cup and Olympics.
Great Britain will compete in the 2019 and 2020 editions in the build-up to the Tokyo Games, with England taking over in 2021 and 2022.
Great Britain’s women take on New Zealand away in their opening game on 10 February, with their first home tie against United States on 27 April.
The men start their campaign away to Spain on 25 January, with the return fixture their first home tie of the year on 4 May.
The women’s side have named 22 players in their squad, with the men naming 25, while nations can use up to 32 players across the entire Pro League.
Holcombe midfielder Middleton is not scheduled to feature at all in the tournament.
GB women’s squad: Giselle Ansley, Grace Balsdon, Sophie Bray, Nicki Cochrane, Amy Costello, Emily Defroand, Sarah Evans, Sabbie Heesh, Tess Howard, Jo Hunter, Hannah Martin, Lizzie Neal, Lily Owsley, Hollie Pearne-Webb, Suzy Petty, Ellie Rayer, Sarah Robertson, Erica Sanders, Amy Tennant, Anna Toman, Susannah Townsend, Laura Unsworth.
GB men’s squad: David Ames, Liam Ansell, Will Calnan, David Condon, Brendan Creed, Adam Dixon, Alan Forsyth, James Gall, Harry Gibson, Mark Gleghorne, David Goodfield, Chris Griffiths, Michael Hoare, Harry Martin, George Pinner, Phil Roper, Liam Sanford, Ian Sloan, Rhys Smith, Luke Taylor, Zach Wallace, Jack Waller, Sam Ward, Henry Weir, Ollie Willars.