All Strachan noticed about his most high-profile signing was that the Corkman was itching for action in this afternoon's match against Clyde, where his presence . . . from the start or the bench . . . has elevated this Scottish Cup tie to the level of an international event.

"I sensed it in his body language. He has really stepped up a level this week, involvement-wise. He is ready for it, " observed Strachan. It is now 16 weeks since Keane played a competitive match, and while the broken toe he sustained in that game against Liverpool has long since healed, Strachan knows the former Manchester United captain needs time out in the middle of the park.

"We've tried our best to recreate game situations as much as we can in training, although conditions are a problem. But it's games you need for match sharpness."

The visit to Broadwood represents the first time Keane has been eligible to play for his new club; under registration rules, not even reserve team matches have been possible.

Strachan offers a little aside on that point, playfully suggesting Celtic chief executive Peter Lawwell would have relished the prospect of a few reserve team outings for the new recruit since they would probably have guaranteed 60,000 through the gate.

It was a light-hearted remark, but it reflected the reality of the interest in Celtic's new number 16. For all Strachan may insist today's match is not about one individual, it is hard to escape the Keane effect, which goes well beyond the hundreds of jerseys flying out of official club stores and the many more 'Ireland United' tops now being worn by Celtic fans who cannot wait to see Neil Lennon and Keane in harness.

The frustration for today's opponents is that their 8,000 capacity limits revenue-generating opportunities. Still, Clyde should clear £130,000 from the fixture, with 300 corporate guests entertained by a club that normally counts itself lucky to have 60 folk in their corporate boxes.

And it's fair to say the 'prawn sandwich' brigade . . . if such a thing exists in Cumbernauld . . . are not turning up to marvel at Ross Wallace's transformation from diminutive winger to doughty left-back. It is a 34-year-old from Cork who is the lure.

Broadwood may not be the most glamorous setting for one of the most anticipated debuts in recent memory, but Keane has always maintained his work ethic ensures he puts as much into training in front of five people as he does playing in front of 50,000.

Last week the West Brom manager Bryan Robson and Strachan had a conversation which eventually got round to the topic of a certain Corkman and why he is not now a member of the first team at The Hawthorns. "He said 'how did you get him because we were offering fortunes'.

And I said 'well, I had the Joker . . . he wanted to come here'. It wasn't me, he just wanted to play for Celtic."

Today that ambition will be fulfilled. Since signing in mid-December there has been much debate about how and where Keane would fit into the Celtic team, but circumstances now present a number of openings.

A hamstring injury picked up last week at Tynecastle by Stilian Petrov, which has not proved as bad as first feared, opens up a space alongside Neil Lennon in midfield.

Meanwhile, Bobo Balde's departure to the African Cup of Nations leaves a gap at the heart of defence. Chris Sutton, of course, might have filled either berth, but he is already off to Birmingham, freeing up wages, but robbing Celtic of their most experienced utility man.

Strachan, while enthusing that Keane can play either centre midfield or central defence, is still more likely to give him his more natural role in the team's engine room, leaving a choice between Adam Virgo and Du Wei to partner centre-half Stephen McManus.

The next question is how much of today's game Keane will play. Strachan offered a tantalising answer when quizzed on whether he had a specific role in mind for Keane during the match against Clyde.

"I know where he will be participating and when he will be participating, " he teased. While it is hard to imagine Keane wanting anything less than a starting berth, there is an argument that an introduction after halftime, perhaps with Celtic ahead and Clyde's energies sapping, would be the more cautious approach.

The manager obviously expects Keane to have a major impact on the pitch, but he has already been impressed by what he has seen off it. In training, the, perfectionist has been tough with some of his younger teammates, but in a way which has pleased his manager. "He is stern, but he explains why he is doing it at the same time, which is great.

I remember being at Dundee and there were older players who talked to me well and then ones who just abused me. Those who were abusive were not interested in helping, " he recalled.

Too much troubled water has passed under the bridge for Strachan to suggest Keane is a paragon of virtue. Such an intense winning mentality brings with it volatility and notoriety. No wonder some bookmakers are offering 5-2 he will be cautioned this afternoon.

"You can bet on anything these days, " observed Strachan, seemingly unconcerned. "What I don't like is them offering odds on managers being sacked." Last season Keane received 15 bookings, but it was still his first full season at Old Trafford where he didn't receive a red card. Maybe time, after all, has brought greater restraint. Or maybe not.

A successful debut will delight Strachan. For after a dismal night in Bratislava at the start of his reign, he pledged Celtic would make the most of their domestic campaign. Seven points clear in the league, with a CIS Cup semi-final against Motherwell next month, the Scottish Cup is the final part of a possible treble. "Let's see where we end up, " said Strachan cautiously.

Who, at the start of the season, would have thought Celtic would have ended up with Roy Keane.