The European Champions Cup is back - and so are the frontline Scottish players after the autumn internationals. Yes! That's until you see who Glasgow Warriors and Edinburgh are playing in the opening round this weekend. Oh, no!

Warriors travel to Sandy Park, Exeter. They don't quite eat their young in Exeter, but they are one mean team.

The English and European champions have some Glasgow legends in their ranks, just to rub it in. They're the continent's greatest force, so offer up a prayer for the Warriors. They'll need all the divine help their fans can muster.

On the face of it, Glasgow and Edinburgh are competing in two competitions this season. In reality, it's just one. And Europe is the one.

When you're shorn of so many players in the Pro14 because of Test defections, when you're missing a dozen and more stellar names and don't have the academy strength or the financial heft to plug all the gaps in what is supposed to be your bread and butter tournament, then you really don't have much of a chance.

Glasgow have two wins from eight, Edinburgh have two from seven. The pair of them are second bottom in their respective conferences in what has been an utterly joyless season so far.

With further interruptions due in the spring when their Test players vanish all over again, the Pro14 is virtually a write-off. Glasgow's misery has been compounded by the prolonged absence through injury of their two marquee signings - Richie Gray and Leone Nakarawa.

Home win a must for Edinburgh

Now that Europe is back, so too is the cavalry. Hope springs. Sort of. Against La Rochelle, coached by Ronan O'Gara, Edinburgh are putting out a gnarled team instead of a callow one.

They have to win. The truncated nature of the tournament this season - four pool matches will determine whether they carry on the Champions Cup, drop down to the Challenge Cup or disappear altogether - means that a loss on Saturday is as good as a knockout blow unless you're intending to deliver heroics on the road to make up for it.

La Rochelle have all sorts of muscle in Uini Atonio, Will Skelton, Kevin Gourdon and the magnificent Gregory Alldritt. They've left out the pace and finishing power and cleverness of Brice Dulin at 15, Arthur Retiere on the wing and the Kiwi Ihaia West at 10 - and still they look strong.

The good news is that what progress La Rochelle have made under O'Gara has come largely at home and not away. Of their last 15 away games, covering all of last season and the early games of this season, they've lost 12 of them.

They beat Pau and Glasgow on the road last season and Pau again this season. That's it. For a squad of players that looks pretty exceptional, and a coaching team that's shrewd, it's a curiously poor return.

If Edinburgh's Test players aren't knackered and their non-Test players aren't demoralised after their Pro14 losses then this is winnable. The great intangible is the state of Edinburgh's mindset. This is their biggest game since the double disappointment of losing to Bordeaux in the quarter-final of the Challenge Cup and to Ulster in the semi-final of the Pro14.

The latter defeat, a capitulation at home, is a ghost that still needs chasing out of town, but there is another dimension to this. Edinburgh have a number of players who'll be on the signing shortlists of various big-hitting clubs in England and France. Even the most monied clubs will have had their spending power curtailed by Covid-19, but for the right guy, they always seem to find enough cash.

Hamish Watson and Jamie Ritchie are both out of contract next summer. Both are outstanding rugby players. It might suit them to stay, but nobody could blame them if they were to accept an offer to go to a club where they might win things, a la Stuart Hogg and Jonny Gray, or somewhere that gives them a better shot at winning things, a la Finn Russell. If Edinburgh are treading water, why would they stick around?

Northern hemisphere's greatest machine

Glasgow had their heart ripped out in recent seasons with the exit of their favourite sons. They're still trying to deal with that.

The return of Gray and Nakarawa was intended to help the process, but the Scot has been out with concussion and the Fijian has been unfit to play. Danny Wilson has most of his Scotland players back in the fold for the trip to Exeter, but he's in full-on survival mode. Mass Test defections, his two big summer signings unavailable and, last weekend, a jaw-dropping last-second missed conversion in front of the posts was the difference between victory and defeat against the Dragons.

With his luck right now, get Wilson to pick 53 numbers between one and 59, work out the six he hasn't picked, enter the national lottery and prepare for victory. Given a choice between a game against the Devil's XV and the Chiefs, Wilson might be minded to ask if there's any difference.

They are northern hemisphere rugby's greatest machine. Almost 60% of their tries last season and this season came from their forwards.

Sam Simmonds, the number eight and European player of the year who can't get a look-in with England, has scored 23 tries in that period. He got eight in this competition last season. He's also got six in three games in the early weeks of the current Premiership, including a hat-trick, his second of the year.

Glasgow know what it's like to play against them, having lost 34-18 and drawn 31-31 in the 2019-20 Champions Cup. A losing bonus point would be an achievement, a victory would be a borderline rugby miracle.

The international players might be back, but the scale of the challenge facing the two Scottish sides doesn't get any easier.