Moore, 18, arrived at Alberton in November after being snapped up with pick No.9 in last year’s NAB AFL Draft.
The versatile midfielder/forward has impressed the Power coaching staff with his hard running and aggression over the summer and Williams said he would be given an opportunity in the pre-season competition.
“We played a massive three quarters of footy on Monday and Andrew Moore stood out really well,” Williams said on Wednesday.
“Jasper McMillan-Pittard looks nice and Scott Harding is coming along really well."
Williams was also to the point in praising the rookie-listed Cameron Hitchcock, who slipped through the national draft much to the Power coach's bemusement.
“I have no idea where in the hell he’s come from and I don’t know why people didn’t pick him, but I’m rapt to see him out here.”
Port Adelaide’s first pick in the 2009 draft, John Butcher, is considered a longer-term project but could also be given a chance in the NAB Cup.
Williams said he would use the pre-season competition to have a good look at the playing list.
“We’re going to give a lot of young players an opportunity to play and see what they can do,” he said.
“There are also a lot of seasoned players that are keen, up and ready to go, so it’ll be a good mix of old and young [in the NAB Cup].”