There’s just one more piece of the puzzle left to fit for St George Illawarra coach Paul McGregor ahead of Round 1 in two weeks’ time.

Saturday night’s Charity Shield in Mudgee answered some questions for the Dragons but their right centre-wing combination remains up in the air.

There’s three players vying for the two spots and McGregor has an idea who he wants to fill them, but admits he needs to make a final decision within the week.

He wants to make a decision as early as possible, so as to get a full week of preparation in before taking on North Queensland in Townsville on March 16.

“It gave me a little bit of clarity where I’m going to go next week, yes,” McGregor said post-game.

“To back that up I’ll watch a lot of footage, talk to my leaders, other coaches and we’ll go from there.”

The three players in question are Euan Aitken, Zac Lomax, and Mikaele Ravalawa.

Aitken is the most experienced of the trio, but his regular spot at right centre is under threat from the two up-and-coming Red V talents.

Aitken and Lomax were the starting centre-wing against South Sydney on Saturday night. Rabbitohs left winger Corey Allan scored a hat-trick.

The Dragons’ right edge defence was a concern all night, and Lomax also missed a tackle on Cody Walker who brushed past his inside shoulder in the second half.

Aitken was benched in the second half and Lomax moved to centre, with Ravalawa coming onto the right wing.

Ravalawa was impressive in last week’s trial against Newcastle, albeit against a second-string Knights side in the second half of the game.

If McGregor desperately wants all three players in the 17, it will come at the expense of young fullback Matt Dufty.

Dufty’s best shot at getting in the side is the bench role. But McGregor confirmed Dufty can only play fullback, meaning the entire spine would shuffle if and when he came into play.

During the Charity Shield Dufty came on late in the game which pushed Ben Hunt (halfback) to hooker, Gareth Widdop (fullback) to halfback, and Cameron McInnes (hooker) to lock.

Aitken or Lomax could well push Dufty off the bench and out of the team.

“If we carry an outside back on the bench we can manipulate that because a centre can go to wing, and one of the halves can go to five-eighth as well,” McGregor said.

Rookie centre Lomax told foxsports.com.au he’s happy to slot in on the wing if asked to.

“That’s up to the coach, if he wants me to play there I’m happy to play there,” Lomax said.

“I’m happy to play wherever, whether that’s centre or wing, whatever.”

In good news for McGregor, Saturday’s final trial seemed to answer one big headache.

The indefinite NRL stand-down of Jack de Belin forced a late switch with Tyson Frizell moving to lock, at least for the foreseeable future.

It brought young forward Jacob Host into the right backrow position, which he handled with aplomb.

“I thought he played well. I thought he was certainly one of the better players on the field,” McGregor said of Host.

“He hit well in D and carried the ball quite strong when he needed to.

“He will find his way into the side.”

The early-season suspension of Korbin Sims means the Dragons will no doubt need to shuffle their starting 13 again within the month.