Six Nations: Pack puzzles & who is lucky 13? Who should start for Scotland?

How will Scotland shape up after a disappointing World Cup?

When Scotland got dumped from the World Cup by Japan, everybody knew that change was coming in its wake. We just had no idea of how much change.

Three players have retired - Greig Laidlaw, John Barclay and Tommy Seymour - and one has been suspended - Finn Russell. Injury has robbed Scotland of Darcy Graham for the opening game against Ireland on Saturday.

Others who were once chosen ones - Ryan Wilson, Pete Horne and Duncan Taylor - have been jettisoned for now. There's a new captain in Stuart Hogg, a new defence coach in Steve Tandy, a new scrum coach in Pieter de Villiers.

When Gregor Townsend names his team for Dublin on Thursday, there could be upwards of nine changes to the side that lost to Japan, some enforced, some thrust upon him, some of them tight calls.

Obvious replacements among backs

Seymour and Graham were the starting wings against Japan, so that's two new men required right away. Easy decisions, these. Blair Kinghorn on one wing, Sean Maitland on the other and we move on.

The midfield combination is slightly harder to call. Sam Johnson will surely start at 12, where it's time he reminded people what an influential player he can be.

Chris Harris took the 13 jersey off Taylor at the World Cup and he remains a Townsend favourite, but Huw Jones has come back into things like a thoroughbred and his case must be irresistible given that his attacking game has returned to pin-sharp level and his defence is vastly improved.

Missing the World Cup was a blessing in disguise for Jones. It gave him the chance to rebuild his confidence and work on his game. He's looking terrific. If a new and improved version of the 2018 Jones has returned, then that midfield looks dangerous. Not blessed with physicality, but Townsend doesn't have a Bundee Aki in his ranks.

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Jones and Johnson with Rory Hutchinson and possibly Harris on the bench as utility cover is encouraging.

Adam Hastings will be at 10 and the good wishes of the nation should go with him. Your first Six Nations start is a tough enough prospect no matter who you are playing, but getting that start against a Finn Russell-dominated backdrop and against a wounded Ireland in Dublin is a major task.

The good news is that Hastings is in excellent form and is not the type of guy who will be fazed by the job. The bad news is that Ireland's back row will be gunning for him.

Josh van der Flier is a speedster and a heavy hitter, CJ Stander is a bull masquerading as a rugby player and between them is Caelen Doris, a debutant who can do the lot, the rapier and the bludgeon. All of them will want a piece of Hastings. It's by a million miles the biggest game of his life.

Townsend has two scrum-halves in form. Ali Price, given his experience, will probably get the nod ahead of George Horne, whose impact off the bench could be of massive significance if Scotland are good enough to stay in the hunt long enough for him to make a difference when he comes on.

Questions to answer in the pack

Will Magnus Bradbury join Edinburgh team-mates Hamish Watson and Jamie Ritchie in the back row?

The pack is an area of uncertainty. Allan Dell is the mainstay at loose-head but he hasn't been starting much for London Irish.

Rory Sutherland appears to be his competition. Sutherland is far from first choice at Edinburgh - Pierre Schoeman is - but it was interesting to hear Townsend bigging up Sutherland's scrummaging performance away to Bordeaux a few weeks back. Was there a clue there? Sutherland stood up well on the day against a brutish pack.

Loose-head is a major problem area given that Tadhg Furlong lies in wait for whoever Townsend opts for. De Villiers might even make this call. If it goes on pure scrummaging, then Sutherland might get a shout for what would be his first cap in more than three-and-a-half years.

There are debates right across the front row, but Fraser Brown's form is better than Stuart McInally's and he should make it. If it's a form call, and not done on reputation, then Zander Fagerson will be at tight-head.

WP Nel is still the cannier scrummager, but Fagerson is flying right now, he's reminding everybody what a special player he could be if he kicks on in anger. He's got everything required to be a world-class tight-head apart from a streak of menace.

Recent weeks indicate that he's working on that side of it. He has a good mentor now in De Villiers, an operator who knew every trick and who pulled every stroke known to scrummaging in his glory days.

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Who will partner Jonny Gray in the second row? Scott Cummings would be the pick here. He's got an extra something on the others - some footwork, some carrying, some dog.

Unless Scotland can meet Ireland head on in the collisions then the Test will be lost. Cummings can do that and he can play. He's got the skill-set to get in behind the Ireland defence and to put others in. It wouldn't be a surprise if Townsend deemed him ready to start.

Jamie Ritchie and Hamish Watson will be on the flanks and two more nuggety characters would be hard to find. Magnus Bradbury, if fit, will probably be the number eight.

Bradbury at Twickenham last year is Scotland in microcosm; anonymous for 40 minutes, then electrifying. Maddening, in other words. He's got the size, the power, the engine, but the question is does he have the mindset to put in a thunderous 60 or 80 minutes like the best do?

He can't flit in and out anymore. He has to be better than that, for his own sake and for Scotland's. Bradbury has to play with a rage or else he may as well not be there and Nick Haining should get a shot. What's it to be, Magnus? Who's it to be, Gregor? We'll know on Thursday.