City fear Silva will be ruled out of derby David Silva is a major doubt for Sunday's Manchester derby after he was ruled out of Manchester City's Champions League match against Borussia Dortmund on Tuesday night with a hamstring injury. Losing the Spain playmaker for a game which could have a significant bearing on the Premier League title race would be a major setback for Roberto Mancini, City's manager. It's a hamstring. We will try," said the Italian. Silva, 26, who provided more assists than any other player in the division last season, has already missed key games after suffering a hamstring injury on international duty with Spain in October. City trail Manchester United by three points in a title tussle that is threatening to become a two-horse race. However, there was potentially bad news too for Sir Alex Ferguson yesterday with Martin Atkinson appointed as the referee for the match at the Etihad Stadium. The official has been the subject of previous complaints from the United manager, who was handed a touchline ban and fined £30,000 by the Football Association in March 2011 for comments about him following his side's 2-1 defeat to Chelsea. Speaking after the game at Stamford Bridge, Ferguson said he had "feared the worst" after hearing Atkinson was in charge of that Premier League match. Atkinson decided not to send off David Luiz, the Chelsea defender, for tough tackles on Javier Hernandez and Wayne Rooney, which provoked Ferguson to say then: "You want a fair referee, or a strong referee anyway -and we didn't get that." Ferguson's touchline punishment comprised a three-game ban for the Atkinson remarks and the activation of a two-game suspended ban he earned the previous season for saying referee Alan Wiley was not "fit enough" to keep up with play.