PORT Adelaide is set to blood four players against St Kilda on Sunday, including prized draft pick Chad Wingard.

Jarrad Redden, John McCarthy and Brad Ebert will also make their Power debuts.

Despite weighing just 77 kg, coach Matthew Primus says Wingard has earned his spot.

"There's not much of him, but he's a real competitive kid, puts his head over the ball and he's been really good in some of the real tough games we've played in the NAB Cup," Primus said.

"The heat's in the kitchen, it certainly will be on Sunday and we're confident he'll be able to stand up under that."

Sunday's match will be Redden's first in the AFL after impressing throughout the pre-season, while Ebert and McCarthy have played for West Coast and Collingwood respectively.

"They deserve [their spot in the side] - they're not getting it because of where they were drafted or how young they are," Primus said.

"Jarrad's been fantastic for us, he's had to stand up for us and we've been delighted with how Chad's gone about his footy."

While four will debut, reigning club champion Jackson Trengove and the exciting Robbie Gray will both miss Sunday's game through injury.

Trengove broke his finger against Melbourne in the Power's final NAB Cup clash, while Gray strained his hamstring at training on Monday.

Gray spent more time in the midfield over the pre-season and shaped as a valuable asset to the Power's engine room. His absence, along with Trengove's, is a blow to the side, but Primus said replacements were abundant.

"He's a guy who can win his own ball, he can turn contests from 50-50 ones into ones that go our way," Primus said of Gray.

"So it is disappointing… [but] our midfield group, we've rotated it a fair bit over the pre-season, they've all gone well so we've got a lot of guys who are in some good form."

Gray's absence hits hard given the importance of the Power's midfield in 2012.

The coach spent the pre-season firing up his players' competitive spirit and said he needed the midfield to win the contested ball a lot more.

"We've got to be able to get the ball inside 50 more, we've got to be able to find more guys who can win their own ball and we think we've added to that mix," he said.

"McCarthy and Ebert have added a bit of depth to it and every other player has nearly had another year under their belt.

"Whether it's the Boaky's (Travis Boak) who are in their sixth or seventh year or whether it's guys in their second or third."

Sunday's match between Port Adelaide and St Kilda kicks off at 4.10pm at AAMI Stadium.

Harry Thring covers Port Adelaide news for AFL.com.au. Follow him on Twitter: @AFL_Harry.