Manchester United defender Rio Ferdinand could miss the rest of the season because of a calf injury.
The England captain suffered the injury in the warm-up ahead of the Premier League defeat by Wolves on 5 February.
Boss Sir Alex Ferguson said: "We aren't looking at this as a short-term situation - we will be lucky to get Rio back for some part of the season."
United have suffered further bad news with defender John O'Shea ruled out for five weeks with a hamstring injury.
Skipper Nemanja Vidic is already missing for the Premier League game against Bolton on Saturday with a calf injury, leaving only four fit defenders available for selection - Fabio, Chris Smalling, Wes Brown and Patrice Evra.
"Vidic won't make it - he is showing good recovery for this week and should be OK after the international break but not enough for Saturday," added Ferguson.
Only a few weeks ago we had every defender fit and things were looking great. It has all just fallen apart in the last week or so
Sir Alex Ferguson
The United manager also confirmed he expects Rafael to be out for "two to three weeks" after the right-back limped off having replaced John O'Shea in the 2-1 win over Marseille in the last 16 Champions League second leg draw at Old Trafford on Wednesday.
Ferguson conceded he may now be forced to take a risk with the fitness of Jonny Evans, who has not featured since standing in for Ferdinand against Wolves, after the Northern Ireland international collected an ankle injury in training shortly afterwards.
"It has been a bad spell for us," added Ferguson.
"Only a few weeks ago we had every defender fit and things were looking great. It has all just fallen apart in the last week or so. Hopefully Jonny Evans may be fit for Saturday, even if it is a bit of a risk."
"He has trained all week but he has been out for such a long time."
Ferdinand's absence will intensify the debate about who will take over the England captaincy ahead of England's Euro 2012 qualifier against Wales on 26 March.
Vice-captain Steven Gerrard is already out of the game after undergoing groin surgery, which is set to rule the Liverpool midfielder out for a month.
Chelsea centre-back and former England captain John Terry played the whole match against the Danes and, although he had to watch on as the captaincy was shared around, there is speculation Capello wants to make him the skipper again.
Terry was stripped of the armband in February 2010 after allegations surrounding his personal life.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.