MACAU Canidrome hero Mr Boo has torn a hind muscle and the fight is underway to have him ready to run again in the Carlsberg Derby in late August. A shocked Canidrome crowd last week saw Mr Boo virtually pull up in a 595-yard race in which he was bidding for his 54th career victory. Track manager Brian Murphy said: ''We knew before the first bend that something was amiss and I suspected it might be a torn muscle. ''He was inspected immediately by the vet and again the following morning. It's a torn muscle which can be very serious for a dog but it all depends on the size of the tear. ''Fortunately this is not a bad tear and we have no doubt that Mr Boo will be racing again,'' he added. Concerned trainer Pat Larkin has lavished attention on his injured kennel star and said: ''It's bad luck but that's the way it happens. ''I will do nothing with him for six weeks at the least, probably two months. But from what the vet says and my own observations I have no doubt that he will race again all right. ''This is not uncommon in dogs and they do come back all right as long as it is not bad and they are given rest,'' added Larkin. The prime target for Mr Boo has always been the Carlsberg Derby in August as this is the big race he has never won. There is now no doubt that it is the only race for which he will be aimed. Said Larkin: ''If we give him the full two months off we are still in nice time for the Derby. I would want to bring him back steadily and I am hopeful that I can do it.'' Mr Boo will now miss the Scottish Night which has been penned in for June 12 which is also the night of the annual Dragon Boat Festival. Negotiations are continuing with three sponsors but there is no doubt that the Canidrome will turn tartan on the big night with an expected crowd of over 200 coming from Hong Kong for the occasion. ''It's a pity that Mr Boo won't be racing on that occasion as I know Pat would have been setting him for one of the Cup races on the night.''