irb.com and James Mortimer 13.Jan.2014Getty Images
Samisoni Viriviri is also included, having pledged himself to the Fiji Sevens side for the remainder of the Series before taking up his new contract with French side, Montpellier.
Outstanding forward Jasa Veremalua is unavailable because he is still rebuilding his fitness after a long term injury, while Pio Tuwai will attend camp next week.
"Jasa still has some work to do to get his fitness back up to par. He understands the work that he needs to do to get fit again," said Ryan.
"Pio's wife is ill at the moment and I respect his decision for missing the first camp. He is keen to come back to camp and will join us next week.
"We have a strong squad with some niggling injuries due to the high volume of training that the team has been going through this week."
Ryan, whose side currently lies third in the Series, will cut his squad of 17 to 12 next Thursday.
In Las Vegas they face a tough trio of pool matches against New Zealand, Australia and Scotland.
Fiji training squad (17): Apisai DOMOLAILAI, Benito MASILEVU, Donasio RATUBULI, Emosi MULEVORO, Henry SENILOLI, Jona TUITOGA, Leo NAIKASAU, Levani BOTIA, Marika VUNIBAKA, Mosese MAWALU, Osea KOLINISAU, Pio TUWAI, Samisoni VIRIVIRI, Samuela SAQIWA, 15. Semi KUNATANI, Viliame MATA, Vucago BAINITABUA