'Something is clearly missing' with the 2010-spec Michael Schumacher - that is the view of the German legend's former sparring partner-turned-BBC F1 pundit David Coulthard eight races into the present campaign, opining that the Mercedes Grand Prix star 'resorted to some pretty questionable racing' in the Canadian Grand Prix in Montreal last weekend.

Pre-season, Coulthard had urged that following three years away from the cut-and-thrust of frontline competition since his original 'retirement', Schumacher should be given a period of grace to re-acclimatise and prove to everybody that he is still the same force that he once so irrefutably was - but with 'one step forward, two steps backwards' in recent races, the Scot concedes that time is now running out.

'Schumi' endured a torrid time of things around the Circuit Gilles Villeneuve in Montreal - previously a happy hunting ground indeed - as he clashed with Renault's Robert Kubica and erstwhile Ferrari team-mate Felipe Massa and looked somewhat inert as he found himself overtaken by the Scuderia Toro Rosso of S?bastien Buemi and Force India duo Vitantonio Liuzzi and Adrian Sutil in the closing stages to take the chequered flag outside of the points in a lowly eleventh place.

That prompted BBC F1 commentator Martin Brundle - another of the record-breaking multiple F1 World Champion's former team-mates - to slate his performance as 'appalling' and the 'worst weekend since he came back', and Coulthard tends to agree, suggesting that Schumacher's much-hyped return is looking increasingly like a very high-profile mistake.

"He has won a record seven times on the ?le Notre Dame, but in all honesty he looked a shadow of his former self on Sunday," the 13-time grand prix-winner and Red Bull Racing consultant wrote in his regular column for The Daily Telegraph.

"He pitted three times and was still lapping over four seconds off the pace in his final stint. He just could not get his tyres working, and in my view resorted to some pretty questionable racing in an effort to hold position. He was particularly fortunate to escape sanction for the late collision with Massa, his old prot?g? at Ferrari. The rules are clear - you cannot make two moves under braking. I'm not sure why they let him off.

"I'm not beating up on Michael. We have had our differences in the past, but I have tremendous respect for him and I have consistently said we need to give him half a season before we judge his comeback. With eight races gone and eleven to go, though, we are getting dangerously close to that tipping-point.

"What is wrong with him? I don't know, but something is clearly missing. It seems a case of one step forward, two steps backwards at the moment. I don't think the reactions have gone, his fitness is fine and to be fair to him he has shown glimpses of his old racecraft - the move on [Fernando] Alonso on the final lap in Monaco was like a visitation from the ghost of Schumi past."