The Black Cats have been severely hampered in recent weeks by having to make early substitutions which have disrupted the plans on which they have worked on the training pitch.
Lee Cattermole and Kieran Richardson had both limped off by the time 23 minutes of the 2-0 home defeat by Liverpool on March 20 had elapsed, while both John Mensah and Richardson again failed to last beyond the half-time whistle on Saturday as West Brom won 3-2 at the Stadium of Light.
Stricken: Lee Cattermole is one of a number of players to suffer with continual niggles that rule him out of games
Bruce has repeatedly insisted he does not want to make injuries an excuse for the club's disastrous run of form, which has seen them collect just a single point from their last eight Barclays Premier League games.
However, he is concerned at the regularity with which he is having to make early substitutions.
Bruce said: 'It isn't happening on the training ground, it happens out there all the time in the match. It's something we will have to analyse. It is not a coincidence. We have had five operations and all five of them have broken down, so it is hampering us.
Can't look: Sunderland have picked up a miserable one point from a possible 24
'I am not trying to blame anybody - I will take the blame - but we will have to look into it as to the reason why it keeps recurring like it is at the moment.'
Bruce's team on Saturday included two men - defender Michael Turner and striker Danny Welbeck - who have just returned from long-term knee injuries, while Fraizer Campbell is close to doing the same.
However, Titus Bramble is struggling to play again this season because of a cartilage problem and keeper Craig Gordon is currently fit enough only to sit on the bench as he continues with a specially-designed programme designed to help him avoid knee surgery.
In addition, midfielder David Meyler has managed only five appearances this season because of serious knee injuries, making Bruce's concern understandable.
He said: 'It's been particularly frustrating from the offset, really, that we have had big trauma injuries to big players of ours.
'Unfortunately in the end, it does catch up with you. You can maybe get away with it for a couple of weeks, but when you are talking months like Michael Turner and Fraizer Campbell and David Meyler and Danny Welbeck.
'Everywhere I look, people have missed three and four months, which has been far, far too many, and that's why I have got to ask now why, why is it us? We will try to get to the bottom of that, if I can.'
Hurry back: Danny Welbeck should relieve some pressure as he finds full fitness
Sunderland's woes have been compounded by a slide from the fringes of the race for Europe to 13th place, where they remain vulnerable to an attack from the sides below them desperately fighting the pull of a relegation zone.
The Black Cats are six points clear of trouble with six games left to play, but head for Bruce's former club Birmingham on Saturday knowing a continuation of their recent form could prove disastrous.
However, their remaining fixtures include clashes with the Blues, Wigan, Wolves and West Ham, who are all worse off, and their fate remains within their own hands.
Pure delight: West Bromwich Albion's Paul Scharner nabbed a late winner at the Stadium of Light
Saturday's defeat by the Baggies, a game in which they twice led, did not go down well on Wearside, although Bruce continues to enjoy the support of owner Ellis Short and chairman Niall Quinn.
But fans who were more than dismayed at Darren Bent's ?24million for Aston Villa in January have started to voice their disapproval at a run which has seen the club win just once in the nine games since.
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Explore more:People: Michael Turner, Darren Bent, Steve Bruce, Danny Welbeck, Lee Cattermole, Titus Bramble, Niall Quinn, Craig Gordon Places: Birmingham, Liverpool, Europe