Istabraq decision A decision on whether or not Istabraq will race again is likely to be made this week.The former champion hurdler injured a hock at Cheltenham last week that resulted in him being pulled up.That discovery has delayed what many thought would be his inevitable retirement but Aidan O`Brien said yesterday: 'We will assess how he is doing during the week.' He also confirmed he is seriously considering giving Johannesburg a run in a new £50,000 race on the all-weather track at Lingfield on Grand National day (April 6th). Johannesburg`s owner Michael Tabor said last month that the Gladness Stakes was the likely starting point for the colt`s season, followed by the Kentucky Derby.However, a new race on the Polytrack surface at Lingfield appears a more likely option with Kentucky in mind. 'I don`t know for certain what we will do yet but Lingfield is a definite possibility,' O`Brien said.