DEERFIELD, last season's Hong Kong Derby favourite, is on the comeback trail following the serious leg injury which made him an 11th hour absentee from that event. The former private purchase griffin sensation, who only raced twice last season after winning all three starts in his debut campaign, has been walking and trotting for the last three weeks. Trainer Alex Wong Yu-on will map out a race programme after a barrier trial on the grass. ''So far, so good,'' says Wong. ''But he has to pass a trial before he can race and we won't really know how his leg stands up until after that piece of fast work. ''It would be too soon to risk him on the grass next Tuesday so we will wait until the grass trials at the beginning of October.'' Wong also had news of another potential star, Winning Chance, the American-bred private purchase griffin who created such a stir when bolting home in record time on his only start last season. ''He is likely to reappear in a Class Three handicap over 1,400 metres,'' said his trainer. ''There isn't a 1,000-metre race for him until the end of October and that is too long to wait. ''Anyway, I've always thought that 1,400 metres could be his best distance as he relaxes so well.'' The new British riders have arrived and Derek Cruz's jockey Gary Carter, who flew in last Tuesday, finally saw some action after having to wait until Saturday for a medical. Carter said: ''I was sat around doing nothing and hadn't ridden for nearly three weeks, so it was good to get out there.'' Dean McKeown, stable jockey to Geoff Lane, passed his medical yesterday. Darren Beadman, Darren Gauci and champion jockey Basil Marcus are all back.