Newcastle United defender Dan Burn is set for an extended period on the sidelines, with manager Eddie Howe confirming he will be out for "four to six weeks" due to a rib and lung issue.

The injury compounds a challenging period for the Magpies, particularly in defence, as they prepare for a crucial Carabao Cup quarter-final.

Burn sustained the injury during Sunday’s Wear-Tyne derby defeat against Sunderland, following a heavy collision with defender Nordi Mukiele.

After receiving medical treatment on the pitch, the towering defender initially attempted to play on but was eventually substituted in the 42nd minute, replaced by Fabian Schar, and subsequently taken to hospital.

Speaking ahead of Wednesday’s cup clash against Fulham, Howe described Burn’s absence as "a big blow," highlighting his importance to the squad.

"It was sort of under the radar in terms of reviewing the game the importance of Dan and losing him, just for everything he brings to the team," Howe stated.

"That was a big blow for us. I think he’s been excellent in recent weeks. It’s a rib problem with some issue with his lungs. We wish him well, it will be probably around four to six weeks."

Dan Burn suffered a painful injury in Sunday’s derby fixture (Getty Images)

Burn’s injury exacerbates an already concerning defensive situation for Newcastle. Key players Kieran Trippier and Emil Krafth remain unavailable, with their target return date around the new year.

Sven Botman, while making progress, is not yet ready to return. Howe admitted the team’s backline is looking "vulnerable" due to a concentration of injuries in the same position.

"The backline is an issue for us. We don’t have many injuries but we have a concentrated group of players that are out and all play the same position. Whenever you get that you’re stretched," Howe explained.

"So our backline is looking vulnerable. With Sven (Botman) we’re not entirely sure when he’ll return. He’s made good progress but I don’t think he’s ready to play yet.

“Then we’ve got Emil Krafth and Kieran Trippier still out, their target date will be around the new year, we think. Jamaal (Lascelles) is just returning from a muscle problem, he’s fit and training with the group."

The upcoming Carabao Cup fixture follows a frustrating derby-day loss at the Stadium of Light, where Newcastle struggled to make an impact.

The Magpies did not register a shot until just after the hour mark, when skipper Bruno Guimaraes forced a save from Robin Roefs, and they struggled to test the Sunderland defence further throughout the match.

Eddie Howe admitted Newcastle are now ‘vulnerable’ due to a number of defensive injuries (AFP via Getty Images)

Guimaraes expressed his frustration post-match, initially labelling their performance "a mess," though he later issued an Instagram apology, urging unity and stating "there’s no time to blame anyone."

Howe addressed his captain’s comments, offering a nuanced perspective.

"I think Bruno’s comments, he was 90 per cent right initially," Howe said. "I don’t think we were a mess, I don’t think the other parts of his original comments were wrong.

“We weren’t a mess, we were very well-organised, we just didn’t deliver the performance we wanted to. I think Bruno’s very emotional and that’s part of his success, that’s why he’s such an outstanding player for us and leader for us.

“As I say, it’s making sure our messaging is right to the outside world, the second statement he put across is 100 per cent right and that’s what we need. The mindset now is we can’t affect the past, we can only affect the future and we need to do that together."

With a crucial cup fixture looming and a growing injury list, Newcastle will be looking to put the derby disappointment behind them and focus on securing a semi-final spot.