Glasgow Warriors' Heineken Cup problems have mounted as winger Tommy Seymour was yesterday banned from facing former club Ulster in tonight's crucial match at Scotstoun Stadium.

The 24-year-old had been cited for a dangerous 'tip tackle' on Northampton winger Vasily Artemyev during their first-round defeat by the English side, and yesterday faced a disciplinary hearing in Dublin where his not guilty plea was dismissed.

However, submissions on his behalf are understood to have included support from Sunday's opponents, which was doubtless a factor in the finding of Simon Thomas, the independent judicial officer, who decided in banning him for a week that the offence was at the low end of the scale, and that the recommended minimum punishment of four weeks would have been "wholly disproportionate".

That does not immediately help his club, whose head coach, Gregor Townsend, felt Seymour's presence was sufficiently important that he accompanied him to the hearing, leaving defence coach Matt Taylor to explain why they are gambling again on having just two backs replacements on the bench.

That proved costly last weekend and, had Seymour been available, Glasgow would have reverted to an orthodox split of five forwards and three backs, making this selection all the more curious and, albeit he felt they had been unlucky with Sunday's turn of events, Taylor admitted there are risks involved.

"There's always a calculated risk when you go 6-2," he agreed. "Talking to Shade [Munro, the forwards coach] and people who have been around for a long time I don't think there's been a period when we've gone 6-2 and we've had injuries to backs. The two tries before half-time probably didn't have anything to do with those changes, it was probably just the way things worked out.

"We were up against a very good forward pack and felt we needed to have that coverage there – that's why we went with that calculated risk."

Fair enough, but Ruaridh Jackson was hobbling during that period before half-time, his decision to stay on looking to be affected by the lack of cover available, and Taylor accepted that the Scotland stand-off's restricted movement had affected the team's capacity to defend when conceding those two tries just before the interval.

"It certainly did on that first try," he said. "We didn't get the set-up that we would have liked. It's a difficult one, but if you're injured you're definitely out and if you're not you've just got to get in the line and get set. It was just disappointing. There were two or three little things that contributed to the line break and one was not getting set up quickly enough and Ruaridh has a job in that department. We've looked at that and hopefully rectified it."

For all the positives that have been talked about there is much to rectify after Glasgow did what would have been inconceivable last season in losing a three-score lead, and doing so within seven minutes either side of half-time. Taylor acknowledged it has left them with a make-or-break match.

"We know that this week is very important to our Heineken Cup campaign. If we lose it makes it difficult for us to go through, but we've got a pretty good record at home. In the last couple of years we've won six of our nine home games so that hopefully stands us in pretty good stead," he said.

Unfortunately, as Taylor also acknowledged, they are up against opponents with a formidable record, last season's Heineken Cup finalists arriving at Scotstoun as the only remaining unbeaten team in Europe's three full-time professional leagues, having registered six straight wins this season.

There has been a real sense that they have generated an additional purpose this season after the death of their youthful centre, Nevin Spence, along with his father and brother, in a freak accident on their family farm.

That has had an effect throughout the province's rugby community, so for all the satisfaction Glasgow officials are rightly taking from the fact that fewer than 500 tickets were still available for this match yesterday afternoon, they can be assured that Ulster supporters will make up a substantial chunk of the 6000-plus crowd.

Even away from home they start as favourites, leaving Glasgow to hope that as Ulster's geographically closest rivals they can produce a derby-type upset.

History offers some encouragement too since, in an odd twist, Ulster were the opponents last time Glasgow played a Heineken Cup tie at Scotstoun, way back in 1997.

They beat the Irish side home and away to reach the knockout stages and will probably have to do so again if they are to make the last eight this time around.

However, they are having to field a very unfamiliar looking three-quarter line since, as well as Seymour's suspension, Sean Lamont has been sidelined by a facial injury which is still subject to further assessment, but Jackson and Stuart Hogg have overcome their injuries to line up in their customary positions.