Auckland Storm centre Theresa Fitzpatrick has been a member of the sevens development squad.
"She's a great rugby player, very powerful, especially carrying the ball. She has great catch and pass skills, and good explosive speed off the mark so that all adds another string to our bow," says Horan.
"We had to make some tough decisions as always with selection. We're looking at bringing some players back and others have had to stay back to work and focus on their bodies to give them every chance for Rio. We want to give all our players the opportunity to put their hands up for the Olympics."
After finishing third at last month's Sao Paulo Sevens, New Zealand is second equal with Canada in the series, behind Australia. The team has been drawn in Pool C at Atlanta and will play USA, Japan and Spain.
Horan said a key goal for the two upcoming tournaments was to achieve a top three season-ending place to ensure the team secured a favourable seeding for the Olympics in August.
"The focus for 2016 was getting the squad ready for Rio and it would be great to win the World Series. Australia has jumped ahead pretty dramatically which is great for the game, but we believe 2016 is not going to be remembered for the series, it's going to be remembered for Rio. Our focus is to get a quality squad with depth that can do the job in August."
Atlanta match schedule:
(Atlanta is 16 hours behind NZT when daylight saving ends on Sunday April 3)
Friday April 8
13.58 v Japan
16.42 v Spain
19.26 v USA
Saturday April 9
Finals
NZ Women's 7s squad for North America tournaments:
Michaela Blyde (Taranaki), Kelly Brazier (Bay of Plenty), Theresa Fitzpatrick (Auckland), Sarah Goss (c, Manawatu), Tyla Nathan-Wong (Auckland), Shiray Tane (Hawke's Bay), Terina Te Tamaki (Waikato), Ruby Tui (Canterbury), Janna Vaughan (Manawatu), Stacey Waaka (Waikato), Katarina Whata-Simpkins (Wellington), Niall Williams (Auckland), Selica Winiata (Manawatu), Portia Woodman (Counties Manukau)