By Tadhg Peavoy

Wales have been poor this Six Nations, surprisingly, and it looks like it’s time for Warren Gatland to begin to switch up tactics and bring in fresh legs, 18 months out from the 2015 Rugby World Cup.

He’s begun to do that this week by making six changes for what is essentially a dead rubber with Scotland, with both teams currently rooted mid-table and out of contention for the title.

Admittedly, some of this is enforced by injury, with Leigh Halfpenny and Rhys Webb ruled out and Liam Williams and Mike Phillips replacing them.

The front row sees Rhodri Jones and Ken Owens come in as Gatland demotes his regular lieutenants Gethin Jenkins and Adam Jones to the bench. Luke Charteris comes in for Jake Ball in the second row.

Luke Charteris in action against Wales

Admittedly these are hardly seismic changes, and more of a subtle nature, but there will be more to come on the summer tour of South Africa, make no mistake.

I also predict a gradual tactical shift for this Wales team away from a pure power game. However, that change will take time, and this time out, Wales will try to do what they do well: beat teams up in the pack and capitalise on the space their strike runners create before offloading into space.

Wales have been poor on the road in Dublin and London, but at Millennium Stadium, especially against France, they reminded everyone what a good side they can be, when they get their set-pieces right, and combine effectively in the backline.

Against England, Wales were more toothless than they’ve ever been under Gatland, as they struggled to make any sort of inroad into the Red Rose’s watertight defensive line.

Their only scores came from penalties when England’s indiscipline was more evident than at any point in the championship.

That would have really worried Gatland and target one this week will be to get Jamie Roberts, George North and Alex Cuthbert carrying with the kind of ferocity they normally do, and making sure the support runners are far more effective in their lines of running.

Jamie Roberts carries against England

If Wales can do that they’ll be largely on the road to victory over Scotland.

The other key area where Wales will be looking to make improvements in is the scrum, where Jenkins and Jones were repeatedly pinged by Roman Poite for crabbing across at Twickenham; fix that and the scrum actually looked very strong and a real weapon for Wales.

Scotland have been a very mixed bag this season, a good first half against Ireland, followed by an embarrassingly poor defeat at home to England, preceded a victory against the odds over Italy, and a narrow defeat to France.

And despite losing last weekend to Les Bleus, Scotland actually produced their best performance of the competition: dominating much of the forward collisions, and playing some quality stuff in the backline.

They did similar away to Italy, with Alex Dunbar scoring two fine tries off turnover ball from the Azzurri.

Alex Dunbar touches down against Italy

Will they be that good against Wales? And perhaps more pertinently will Wales afford them the kind of space Italy and France did? Unlikely.

The manner of the Welsh defeat to England was do damning that Gatland will have read the riot act to his team; if Wales aren’t hugely improved this Saturday it would be the biggest surprise of the day.

The squad were naturally going to be tired after the Lions tour, remember 15 Welshmen travelled out to Australia at the start of the tour; that was also going to have a knock-on effect, and so it has proved as the oomph they normally possess in their attacking zeal has been largely missing.

Scotland, as they aim to leapfrog Wales into fourth in the table, need to target this tiredness in Welsh legs by keeping them moving.

If they have done one thing well over the course of the last two games it’s been spreading the ball to the centres , and using their backrow runners to add extra numbers and stretch the opposition defence. They’ll do the same thing in Cardiff and hope to expose Welsh lethargy.

Dunbar and Matt Scott have been two of the best Scottish performers this spring and good performances from both of them this weekend would begin to convince watching aficionados that they have what it takes to become a regular partnership in the middle for the Dark Blues.

Both sides have scored four tries apiece this championship and that would indicate a close encounter is on the cards in Cardiff.

However, with Johnnie Beattie’s absence through injury, and the inexperience of Dougie Fife on the wing, Scotland might be a little short at the breakdown, and on the flank. Factor in Wales’ desire to right the wrongs of Twickenham and you’d have to back a Welsh win.

Verdict: Wales to win by 18.

Live television coverage of the RBS 6 Nations from 12:00 on Saturday 5 March (12:30 Italy v England, 14:45 Wales v Scotland, 17:00 France v Ireland) on RTÉ Two and (Ireland only). Live radio coverage of France v Ireland on Saturday Sport (14:00) on RTÉ Radio 1 and RTÉ.ie (Worldwide).

Follow Tadhg Peavoy on Twitter here: @TPeavoy