Manchester United manager Alex Ferguson is worried the absence of his regular defenders could affect their bid to win a fourth consecutive Premier League title. The Red Devils suffered a crushing 3-0 defeat to Fulham on Saturday after their makeshift defense was exposed on numerous occasions. They had to do without Jonny Evans, John O'Shea, Gary Neville, Rio Ferdinand and Wes Brown - who are all injured. "I hope that loss doesn't prove too damaging. In other words, I hope it doesn't cost us the league," Ferguson told MUTV after the game. "There was a fragility at the back today, but we couldn't do anything about that. "I have sympathy for my players because it's difficult for midfielders to play as centre-backs and Ritchie De Laet's only 20 years of age so he's not yet got the experience you need for this type of matches." United are second in the league table with 37 points from 18 games, three behind leaders Chelsea who can extend their advantage to six points if they beat West Ham on Sunday.