A shoulder injury ruled Thomas out for the third leg of the world series in Port Elizabeth which saw Wales slip to ninth in the overall series standings but interim head coach Gareth Williams is confident his side can rise to the occasion at the Sam Boyd Stadium.
"We've been around the fifth or sixth mark on the overall series standings this season so it is a bit disappointing to slip to ninth but there are extenuating circumstances for our current position.
"In the last round in Port Elizabeth we really struggled with injuries - we were down to the bare bones on the last day with only seven fit players. But the boys showed a lot of character to hang in there," said Williams.
"That character saw us defeat a very strong Canada side in the Bowl quarter-finals before we bowed out against Australia in the semi-finals but boys heads never dropped and they kept going until the final whistle.
"There are no easy games at this level and in Las Vegas we face a tough group against South Africa, Kenya and Canada but if the boys can reproduce the consistency they have shown in previous rounds prior to Port Elizabeth then we stand a good chance of progression."
Wales will be without key playmaker Lee Williams and finisher Chris Knight along with Alex Walker who have picked up knocks since the last round while Adam Field and Alex Webber are still recovering from long term injury.
Wales Sevens squad for Las Vegas:
Adam Thomas (Pontypridd - Captain)
*Dylan Morgans (Carmarthen Quins)
James Davies (Carmarthen Quins)
Sam Cross (Cardiff Met)
Jason Harries (Carmarthen Quins)
Rhys Shellard (Pontypridd)
Rhodri Davies (Llandovery)
Rhys Jones (Cross Keys)
Will Thomas (Cardiff)
Will Price (Aberavon)
Ashley Evans (Bridgend)
Luke Morgan (Bridgend)