Roy Hodgson says there is "no question" Crystal Palace will feel Mamadou Sakho's absence after he underwent knee surgery on Thursday.
The central defender was successfully operated on, following the injury sustained in last week's victory at Leicester, and there remains a risk he will not return this season.
Sakho's partnership with James Tomkins has become one of Palace's biggest — and certainly most consistent — strengths during Hodgson's time as the club's manager.
That he and Aaron Wan-Bissaka were absent from Wednesday's 3-1 defeat by Manchester United was also noticeable in the way their defence was uncharacteristically so poor.
The £26million Sakho will be replaced for Saturday's fixture at Burnley by either Scott Dann or Martin Kelly and Hodgson said: "We are going to miss him until such time as he gets fit again. There's no question of that.
"He has been very, very good for the bulk of the time I've been here. When I first came he was shrugging off some injuries but since he got fit, he has been exceptional, the latter half of last season and the whole of this season.
"Him and James Tomkins together have formed a fantastic partnership. There's no way you can lose a player like that without missing him, but I am fortunate that in Scott Dann and Martin Kelly there are two experienced Premier League players (capable of deputising).
"The most important thing was the surgery was successful. There's no timescale being put on that, but obviously it's a surgical operation, so he's not going to be coming back next week."
Hodgson, at 71 the Premier League's oldest ever manager, also expressed his "disappointment" that former club Fulham "harshly" chose to sack Claudio Ranieri after just 106 days at Craven Cottage – but he believes that in Scott Parker they have a potential successor with the ability to excel.
"Scott was an exceptionally good player, and had a wonderful career at West Ham and Tottenham," said Hodgson, having managed the then-midfielder while with England.
"I've no doubt about his credentials, his potential. He has a nice personality and he has worked hard on his coaching badges, and to develop himself as a coach, though I have no dealings with him on those side of things.
"I can only wish him well, while bemoaning it is at the expense of someone like Ranieri.
"He was a very, very dedicated professional, a very good professional, and someone who maximised his career, who really brought out the best in what he had.
"He was an important member of my team going into the Euros in 2012. We will see how he does.
"I think it is harsh (on Ranieri). It doesn't please me to see this situation, not only for Ranieri, but for Fulham, a club that is close to me."
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