O’Loughlin was rated 50-50 by head coach Wayne Bennett to recover from a quad injury in time for the clash with the Kangaroos but Sinfield, who has joined up with the England squad in Brisbane in his role as the Rugby Football League’s rugby director, thinks he will play.
“Yes, we need him,” Sinfield said. “He has been great.
“Our medical team have been brilliant all tournament and Sean has worked very hard. I have no doubt he will play.”
Bennett said after yesterday’s opening training session at Ballymore Stadium that a final decision would be made on O’Loughlin’s fitness before the captain’s run at Suncorp Stadium tomorrow.
A fit O’Loughlin would be a major tonic for England, who have lost their first-choice hooker Josh Hodgson with a knee injury.
Sinfield, who is an ambassador for Prostate Cancer UK, admits the loss of the former Hull KR captain is a blow but is confident England have the resources to offset it.
“It’s really tough for Josh,” he said. “He has been awesome and we are sad to see him injured and facing a lengthy spell on the sidelines. We will miss him.
“It will provide an opportunity for Chris Heighington to come into the 17 though and he has had a great tournament too. James Roby is fantastic and is capable of playing 80 minutes in that crucial hooking role.”
Sinfield says the fact that Australia have not been tested in the tournament since being pushed by Wayne Bennett’s men in their opening 18-4 victory in Melbourne will work in England’s favour.
The former Leeds Rhinos skipper, whose last match for England was their agonising 20-18 defeat by New Zealand in the 2013 semi-final at Wembley, knows what victory on Saturday would mean for the game in England and is confident they can pull off a shock.
“It would be huge,” Sinfield added. “We need a 10 out of 10 performance. Players win big games and we have to play well.
“Australia are a great team but we have to believe we can win. I fully believe in this group.”
Sinfield accepts England will need to keep a tight rein on Kangaroos winger Valentine Holmes, who has scored 11 tries in his last two games.
“He is a fantastic player and has had a great tournament so far,” Sinfield said. “I think Ryan Hall and Jermaine McGillvary, our two wingers have been outstanding too.
“It will be a great contest between the wings.”