There was quite a flurry around the Celtic training complex the other day when new signing Erik Sviatchenko was unveiled.

Lucikly I missed the press conference myself, and therefore didn’t have to swot up on fashion nouveau, pop-art and the rest.

What a stir Sviatchenko caused. The guy writes a fashion blog, “Close Up and Private”, dabbles in other literature, and has a famous father, Sergei Sviatchenko, whose art is renowned in Ukraine.

These fripperies around Celtic’s new defender triggered quite a bit of media hot air. And don’t get me wrong – we want interesting characters in Scottish football.

Meanwhile, Celtic fans were asking just one question: can Sviatchenko defend?

The big Dane’s signing this week is the start of a critical seven-month period for Ronny Deila. Celtic’s Norwegian coach is charged with rebuilding his erratic team between now and August, and the fruits of that work will determine whether Deila is a credible Celtic coach for the long term.

Deila now has his base in Jozo Simunovic and Sviatchenko, his ideal new centre-back pairing. In Craig Gordon and Lee Griffiths, Deila also has players at either end of the field that he believes he can trust. So Celtic have a foundation upon which to build.

What must come next, between now and the summer, are three or four key players of proven value and ability, whom Deila can take into next season’s European campaign. It is going to be his defining period at Celtic.

Sviatchenko is a test-case for Deila. No-one, surely, can know the Scandinavian scene better than the Celtic coach? So Deila has made his judgement in buying this 25-year-old, and now we wait to see if that judgement will stand up to scrutiny.

Celtic took a similar plunge with Stefan Johansen, whom Deila called “the best player in Norway” when the midfielder arrived at Celtic Park in January 2014. Johansen has his critics, and suffers fluctuations in form, but in the main he has seemed a decent signing.

Mikael Lustig has also come from Scandinavia and, when fit, has looked an excellent Celtic player. Of course years ago both Johan Mjallby and Henrik Larsson came out of Sweden and served Celtic memorably.

It is – potentially – a productive and affordable market for the Scottish champions to operate in. As are other countries in eastern Europe, such as Croatia, and even Israel.

But for every Lustig or Mjallby there can be a Morten Rasmussen or Jos Hooiveld, who arrived at Celtic under Tony Mowbray and proved disastrous signings. Not to mention Mo Bangura, one of Celtic’s all-time transfer market fiascos when he arrived for £2.5m from AIK in 2011.

There is one other slight concern for Celtic. For some reason, in recent times, Scandinavia has dipped in reputation as a source of talent for the bigger leagues of Europe.

Various clubs have scouted there in the past 12 months and said “no thanks”, including some who looked at Sviatchenko. So the anxiety of matching “value” and “talent” for Celtic is never quite erased. The lottery of it remains.

Deila will have no illusions. He is said to have a good relationship with Peter Lawwell, the Celtic CEO, but that is an utter irrelevance. Celtic will remove their coach if he cannot show real progress, both domestically and in Europe, over the next six to nine months.

There are Celtic supporters who remain deeply unconvinced, and who care not a whit for 8-1 thrashings of Hamilton Academical. To them, such midweek slaughters don’t even enter their thinking when it comes to Deila.

They see a coach who has made next to no progress on the European stage, and whose domestic campaign has so far failed to deal sufficiently with the challenge of Aberdeen. “Deila isn’t up to it, he is out of his depth,” is a common refrain among the Norwegian’s army of doubters.

So let’s see what Deila is made of in this current Celtic rebuild. Let’s put his judgements to the test. Come the autumn – presuming Deila is still in situ – we will know better the mettle of his team.

After arriving from Stromsgodset in 2014, this is the next key period in Ronny Deila’s career.