Manchester United defender Patrice Evra says the growing list of injuries at the club could hamper the champions' title defence.
United beat Wigan 5-0 on Monday, but that win came at a price with Jonny Evans going off at half-time with a calf injury leaving Evra to team up with Michael Carrick in central defence.
Currently, United have 11 men on the treatment table and while Ferguson is hopeful youngsters Chris Smalling and Phil Jones will have recovered from illness in time to face Blackburn on New Year's Eve, Evra knows the present situation is unsustainable.
"I am a little bit worried because we need everyone if we are going to win the league," said the France international.
"It is starting to get annoying.
"It is not the first year we got so many injuries. Two years ago I played with Michael Carrick and Darren Fletcher at the back.
"The most important thing is that we won but I hope everyone gets fit because Blackburn is another big game and we need all the defenders."
Midfielder Park Ji-sung echoed Evra's concerns.
"I have never known anything like it," said the South Korean.
"Hopefully we will get our defenders back pretty quickly because we are coming up to some very important games.
"We have to deal with it and get through this period."
Of those who missed out Monday, Ferguson has highest hopes of Jones and Smalling making a successful recovery from illness.
United have not put a timescale on Rio Ferdinand's absence with a back injury, while Evans looks set to miss a couple of weeks with the calf injury that forced him off at half-time during the Wigan win.