The 27-year-old was on Thursday visiting a specialist after complaining of pain in the knee he injured against Everton in November. Turner had returned to training after damaging ligaments when he collided with a goalpost in November, and Bruce had hoped to have him back at his disposal in a few weeks' time. But as he prepares for Saturday's Premier League trip to Everton, the manager is sweating on the outcome of fresh tests. Bruce told the Sunderland Echo: "Michael is going in for a scan so that we can find out exactly what the problem is. "It is pointless speculating on what might or might not be wrong - we will just wait for the results and take it from there. "The specialist will use a keyhole camera to look inside, and we are keeping our fingers crossed it's nothing serious. "But Michael is as tough a footballer as you will find, so for him to pull up and say he wasn't happy with it tells you something. "He will play through the pain barrier every time, so it's clearly a niggle which has him worried - and it's a tricky one because it was the posterior knee ligaments he damaged originally and even before that injury, he was having a bit of pain there. "It's quite possible the problem he's got isn't anything to do with the injury he sustained last year at all, but the thing that was originally troubling him in the first place." Turner, who joined the club from Hull in August 2009, had proved himself a key member of Bruce's first-choice defence before his misfortune struck. He was injured sliding in to successfully clear a Tim Cahill effort off the line during his side's 2-2 draw with the Toffees on November 22. The defender finished the game, but tests later revealed the ligament injury and he was ruled out for three months, a blow which was compounded by the news that Titus Bramble needed surgery to repair a damaged cartilage. Turner initially had to wear a brace to support his knee, but was closing in on a return to action when he experienced fresh discomfort. Bruce said: "I feel for him and I feel for us. We have missed him an awful lot at the back, where his physical presence and his desire to head clear were major factors in our strong defensive start to the season. "I know how much he was looking forward to making his return a month or so from now. "Hopefully he will not be too far away from that mark and hopefully the scan will provide good news. But for the moment, all we can do is wait and see." Sunderland remain in seventh place in the table despite winning only five of the 13 league games they have played in Turner's absence. They have kept just five clean sheets during that period and have become increasingly vulnerable from set-pieces in recent weeks. John Mensah has partnered Bramble in central defence in the last two games, although his persistent injury problems have limited his participation once again this season. Anton Ferdinand had previously deputised to good effect, while loan signing Nedum Onuoha can play in the middle despite having been used mainly at right-back this season. Meanwhile, Bruce confirmed that Brazilian club Corinthians have enquired about Paraguay midfielder Cristian Riveros, who has struggled to make his mark on Wearside.
