With Wallabies No.10 Bernard Foley battling concussion symptoms, Hegarty has been handed the playmaking duties in the Waratahs' season-opener against the Force at Allianz Stadium.

Waratahs coach Daryl Gibson said the "unusual player", who spent three seasons with the Rebels before moving to Sydney, was hugely popular within the squad, not least because of his unlikely build.

"The reason he's so popular is because he shouldn't be playing No.10 - or rugby - in a really nice way," Gibson said.

"We call him 'Fettuccine', which is a reference to his legs, because they're like spaghetti in that they look like they're going to fall off at any moment.

"But he can play the game, he's got wonderful game sense, a good skill-set and an excellent rugby brain. That's the thing that attracts me to him, he gets the game, he's a rugby player. While he doesn't have all the talents in the world he utilises every ounce of them."

Hegarty signed with the Waratahs ahead of the 2016 season but spent most of the year on the sidelines after suffering a knee injury in March. Foley's extended absence during the pre-season after a gruelling Test calendar last year allowed the Brisbane-born playmaker some solid playing time.

Gibson said while losing a Test No.10 was a setback on the eve of the new Super Rugby season, he had complete faith in Foley's understudy.

"It's never great but if you're going to win this competition you've got to have a good squad and have faith in that squad," he said.

"We've been practising for the last month without him [Foley], for these moments, so I think we're well-prepared."

Foley was injured during the Waratahs' trial match against the Highlanders last week and has been following concussion protocols to determine his return to play. Gibson revealed the 27-year-old was still having dizzy spells and had not passed a computer-based cognitive assessment, but would travel with the team to South Africa for their games in rounds two and three.

It is an undeniable blow for the 2014 Super Rugby champions, who take a young squad into the new season and will be relying on their experienced big names. Young second-rower Ned Hanigan was also scratched from the bench after suffering a hamstring injury, with Dave McDuling filling his spot.

The Waratahs will still pack plenty of firepower into their back line, however. Israel Folau and new recruit Irae Simone are lining up in midfield, with Reece Robinson and veteran utility Rob Horne on the wings and Andrew Kellaway at fullback.

They will come up against a lower-profile but no less exciting back line from the Western Force, with Sydney-raised former Gloucester centre Bill Meakes teaming up with former NRL winger Curtis Rona, and Wallabies outside back Dane Haylett-Petty at fullback.

Kellaway said he expected more creativity from the Force this year under head coach Dave Wessels.

"They're going to have a crack ... you've got [Rona] from rugby league, it will be great to see what he does, and he's up against Izzy [Folau], so hopefully the rain stays away," he said.

In Foley's absence, Hegarty and Robinson would potentially share the goal kicking duties, Gibson said. The Waratahs' territory game will also be put under the microscope after the Highlanders heaped pressure on the hosts with a succession of high balls last week.

Waratahs team (1-15): Tom Robertson, Tolu Latu, Sekope Kepu, Dean Mumm, Will Skelton, Jack Dempsey, Michael Hooper, Michael Wells, Nick Phipps, Bryce Hegarty, Rob Horne, Irae Simone, Israel Folau, Reece Robinson, Andrew Kellaway.

Reserves (one to be omitted): Hugh Roach, Paddy Ryan, David Lolohea, David McDuling, Brad Wilkin, Matt Lucas, Taqele Naiyaravoro, David Horwitz.