Bruce tries to make sense of why Sunderland lack staying power

Sunderland sold Darren Bent to Aston Villa in January (PA)

Exasperated Sunderland manager Steve Bruce is to launch an inquiry into why so many of his players break down in games.

The club 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 20 March had elapsed, while John Mensah and Richardson again failed to last beyond the half-time whistle on Saturday as West Bromwich won 3-2 at the Stadium of Light.

Bruce has repeatedly insisted he does not want to make injuries an excuse for the club's disastrous run of form in collecting just a single point from their last eight Premier League games. However, he is concerned at the regularity with which he is having to make early substitutions.

"It isn't happening on the training ground, it happens out there all the time in the match," Bruce said yesterday. "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. I am not trying to blame anybody, but we will have to look into it as to the reason why it keeps recurring like it is."

Bruce's team on Saturday included two men, the 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 the goalkeeper Craig Gordon is currently fit enough only to sit on the bench as he continues with a programme designed to help him to avoid knee surgery. In addition, the midfielder David Meyler has managed only five appearances this season because of serious knee injuries, making Bruce's concern understandable.

"It's been particularly frustrating from the offset, really, that we have had big trauma injuries to big players of ours," Bruce added. "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."

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 to get away from the relegation zone. The club are six points clear of trouble with six games left to play, but head for Birmingham on Saturday knowing a continuation of their recent form could prove disastrous.

However, with further fixtures against Wigan, Wolves and West Ham, all worse off, their fate remains within their own hands. But fans who were more than dismayed at Darren Bent's £24m departure for Aston Villa in January have started to voice their disapproval at the club's results since.