While the Dragons marched to the top of the ladder early in the year off the back of their representative-laden forward pack, both Mann and Lomax will fill key positions in their backline for the do-or-die match.

Mann's selection at five-eighth for the injured Gareth Widdop (shoulder) is an obvious one, but McGregor's decision to play Lomax in the centres ahead of Euan Aitken - who was available for selection on return from a hamstring tear - is telling.

Aitken was yet to reach 80 per cent speed this week, but McGregor said he had no qualms putting 18-year-old Lomax up against Greg Inglis in just his fourth NRL game, considering the youngster had idolised the South Sydney star growing up.

"If you've grown up watching a player and you grow up with so much respect for the player you learn a lot about them," McGregor said.

"That probably gives him a little bit more of an insight more than anything else.

"It doesn't matter if you're the most experienced player in the competition or the least experienced ... you're going to have the same problem (with Inglis).

"But the kid will go well."

Lomax also offers a chief kicking option with Widdop out, ahead of Tim Lafai.

Jordan Pereria will also hold his spot on the wing in front of retiring veteran Jason Nightingale, who has recovered from an elbow injury.

Also boosted by Jack de Belin's inclusion with an ankle injury, McGregor said he had no concerns with Mann stepping up at five-eighth, after he impressed with limited time there in last week's win over Brisbane.

Mann is also a noted defender after being used in the middle as a utility for most the season, but eventually wants to pursue a career at five-eighth.

"I've got a lot more faith than fear with Kurt playing No.6," McGregor said.

"He's the type of kid who will keep it simple and go to the game. The more simple Kurt keeps it the better he will play.

"Defensively he is very strong."

Australian Associated Press