SAINTS boss Justin Holbrook has made big changes to the spine of his team as he looks to get the edge in the tight games ahead.

NRL superstar Ben Barba will make his Saints debut at full back in Friday’s massive home derby with Wigan.

It means England number one Jonny Lomax returns to the halves - where he played all of his early rugby.

There Lomax will partner the experienced Matty Smith, with Danny Richardson dropping out.

Theo Fages’ role under the new formation is yet to be worked out, although there is a possibility he could take a bench spot to spell James Roby or cover the halves.

Holbrook said: “Full back is Benny’s best position.

“Jonny played all of his junior rugby in the halves before moving to full back.

“Jonny is looking forward to it – and that was important to me because that was a big move.

“He wants the ball more. At full back you can tend to run around a lot without getting your hands on the ball.

“At five-eighth you can get it when you want it.

“The unlucky one is Theo Fages because he’s been playing great for us and is a great little competitor.

“It is a tough decision and that is what we have gone with.

“I have been happy with our squad all along, but the last two games we have fallen short by a couple of points.

“If you have an absolute quality player like Benny in tight games like that it could be the difference.

“That is what we need – a bit of as lift and he will bring that.”

Barba will get plenty of attention from the Wigan side - both physically and with an aerial bombardment.

But Holbrook has faith he can hit the ground running after a 10-month absence.

He said: “Benny is not just a good runner of the ball, he has the skills of a half and vision.

“There are not that many players in this game who have that ability to play what they see, but he has that.

“He has experience too having played there a long time and can get the defensive numbers right.

“His overall game is what we want – they are the things that make him the player that he is.”

Barba has not played rugby league since last year's NRL Grand Final, but he did have a short spell with Toulon rugby union.

There is an expectation of ring-rust, but coach Holbrook expects him to deliver the goods.

Holbrook said: "The fact that he hasn’t played for so long is a bit like the first game of the year.

"Good players still play well on their first game as they do on their last.

"We know Wigan will kick the ball to him, but he has been dealing with that for years and I'm sure he will catch it and run the ball back."

Smith continues at seven, with Richardson dropping out of the 19-man squad.

But Holbrook has been impressed with the young Widnesian - and it does not mean a door slamming shut on him.

"Danny has been going really well and I have a lot of time for him as a player.

"But Matty has got that seven spot at the moment and I am confident he will do a good job for us.

"Danny is only really young, but he has done a great job for us.

"Matty is full of experience – he has been there and done it before.

"He has worked really hard since his eye injury – and he has put a big focus on getting back in the side and has had to work hard to get back in.

"We just think that is the right combination at this time," he said.

The team structure has not been part of a big masterplan, with the Saints boss revealing that decisions were only really made after the Leeds game.

Holbrook will decide whether to go with another big man to take on the abrasive Wigan pack or throw on Fages as someone who can mix it up.

A tough game is in the offing.

"Wigan will play nice and physical, like they always have done, but we are ok with that as we have a few physical boys ourselves," he said.

In stark contrast to years gone by when the side's pivots have been denuded approaching this time of the season, this time around the squad is getting stronger.

It will only be after Barba has played a few games that anyone will see what Saints' crop of 2017 is capable of.

It has added to an exciting run-in, but there is no more scope for slip-ups. Although defeat won't be the end, it will take their destiny out of their own hands which could be fatal with just three games to play afterwards.

"We need to get wins now, but it is exciting as we are still building and improving.

"Although that is the big plus we have to start winning those tight games.

"We know we are a good enough side but we have to execute better, we will run out of time to review missed opportunities and have to be taking those chances now," he said.