Bruce admitted last Friday that his £3.5m signing would miss most of the new campaign if surgery was required and his worst fears have now been realised, with Campbell preparing for another lengthy lay-off.

Bruce told the Sunderland Echo: “Fraizer gets operated on today. He will be out for 12 months.

“He was out on the training ground yesterday having a bit of banter with the players. He’s taken it okay because he is strong mentally.

“Thankfully, with his strength of mind, we think he will be okay. I hope he will be. If there’s anyone mentally tough enough, it’s him.”

Campbell’s trip to the operating theatre came just 48 hours after goalkeeper Craig Gordon had surgery on his injured knee which will rule him out for up to six months.

However, while Bruce has Belgium international Simon Mignolet as a ready replacement – the 23-year-old’s poor day at Birmingham last weekend was in stark contrast to his recent form – strikers are currently painfully thin on the ground at the Stadium of Light.

The manager has conceded that, with hindsight, the decision to sell Darren Bent to Aston Villa when they came calling with a cheque for £24m in January might have been an error, although he insists there was little point in trying to hang on to a man who had clearly made up his mind to go.

Sunderland have played 10 Premier League games since Bent defected to the West Midlands, and have won just one of them.

More alarmingly, they have collected a solitary point from the 27 on offer since beating Blackpool on January 22 to slip out of contention for European qualification to the fringes of the fight for survival.

Those 10 games have brought just nine goals; Bent has scored six for Villa during the same period.

The Black Cats took the decision not to spend in haste to replace the former Tottenham man despite loan signing Danny Welbeck having earlier suffered a knee injury, preferring instead to prepare themselves fully for the summer market.

They recruited forward Stephane Sessegnon and midfielder Sulley Muntari in January with Bruce confident that within a matter of weeks, Campbell would be back in harness.

However, his progress came to a juddering halt two days before the club’s trip to Manchester City – the club against whom he had suffered the original injury on August 29 – when he twisted his knee in training.

Bruce said: “In January, I was looking at March and April for Fraizer to be fit, and he was making such great progress.

“It stopped me from going for another striker because I thought Fraizer would be fit in six weeks.”

With Welbeck suffering a hamstring strain at Birmingham, Bruce faces heading into Saturday’s home clash with Wigan – a game he cannot afford to lose – with just one fit striker in the shape of Asamoah Gyan.

He could once again play midfielder Kieran Richardson as an auxiliary striker, he scored twice in that role at Blackpool – provided he recovers from his hamstring problem.

But Campbell’s misfortune has brought home the need to Bruce that he must add significantly to his pool of strikers, with Welbeck set to return to parent club Manchester United at the end of the season.

The manager said: “It puts a bit more pressure on us for next season. Going forward as a club, we have to look to get over it because in the summer, we have got one striker.”