Motor Racing: Door is open for Rainey or Schwantz: Patrick Miles sorts out the wounded riders from the definite non-starters in Sunday's British 500cc Grand Prix at Donington

THE ABSENCE of the world championship leader, Michael Doohan, from the British 500cc Grand Prix here this weekend has injected life into a series that earlier in the season appeared to be heading in the same direction as its Formula One counterpart.

The Australian had won the first four races of the year, finished second in the next two and then won another, but a serious accident during qualifying for the eighth round, in the Netherlands, has given his rivals a stronger vision of the title with three races, including this one, to go.

Among those who know well the pain that Doohan has suffered from his badly broken leg, but who will grab the opportunity his period of mending presents, is Kevin Schwantz, the American who, like Doohan, awaits his first 500cc title.

Schwantz is the race favourite going into today's first qualifying session, by virtue of his familiarity with the vagaries of this curvy 2.5- mile circuit which has more than once driven a rider round the bend. Schwantz has won three on the trot here for Suzuki.

But he must carry an injury into the event, one that, when it occurred, placed his short-term participation in doubt. Schwantz broke his left arm, which required a metal plate, and also dislocated his pelvis in a crash at Assen, the day after Doohan lost contact with his Honda.

Schwantz would have missed the next grand prix but intensive therapy from Dr Claudio Costa, the travelling bone specialist who has a clinic near Imola, had Schwantz, who could barely walk, back on board for Hungary where he came fourth and scored valuable championship points.

The past year has been one of physical hurt for almost all the leading riders on the circuit. For Wayne Rainey, the world champion, the litany of woe began in the last race of 1991 in Malaysia, where he fell and broke his leg, and since then there have been enough bad injuries to suggest that greater risks are being taken, that the closeness of the competition in 500cc racing has increased the need for speed.

Rainey is not known as a rider who gets kicked off very often. His leg took the winter to heal and this season he has suffered, among other ailments, a hand injury that kept him out of one race and kept him quiet in several others. It does not normally happen like this.

Doohan was Mr Perfect, then he smashed up at Assen. He has had circulation problems in his broken leg, he has had it in a decompression chamber, he has had skin grafts and, it has been reported, he was faced briefly with the possibility of amputation. His team-mate and countryman, Wayne Gardner, a Honda stalwart for years, crashed in the first race of the year at Suzuka and was out of contention until round seven. One race later, he was back in the circuit hospital with concussion and bruising.

John Kocinski, another strong contender for Sunday's grand prix, has been affected by an unidentified virus all year, and he mangled a little finger so badly in Australia that what was left of it was removed.

There will be a fair proportion of walking wounded for the British Grand Prix, not that they would admit to feeling ill. There are too many other riders who are eager to take a psychological advantage.

Niall Mackenzie, the experienced and determined Scot from the Banco Yamaha France team, will be carrying British hopes here. Mackenzie made a rare visit to the podium in Spain and came sixth at the last meeting in France.

The 31-year-old former British champion was fourth in the 1990 world championship but he lost his place in a works team and had to compete with a smaller budget and an inferior bike. Mackenzie's fighting spirit could carry him to a finish in the top six on Sunday.

But the pace in the race will be set by the Suzuki and Yamaha of Schwantz and Rainey, respectively. Rainey, who has won two grands prix this season, trails Doohan by 37 points and leads Schwantz by six. With 20 points for victory, and Doohan expected to miss the next round as well, the title is available.