New Dundee United manager Jackie McNamara has invited Swedish defender Marcus Tornstrand for a trial. McNamara is feeling a bit exposed at the back after Gavin Gunning picked up a knee injury which could see him ruled out for the rest of the season. Former Hammarby player Tornstrand has linked up with the club for a training stint and McNamara has challenged him to impress. McNamara said: "We'll have a wee look at Marcus. I haven't seen all that much of him and the difficult thing is trying to get a game to have a look at him in. But I know he has played for Sweden's Under 21s. The transfer window is shut just now so there's not a lot we can do but we'll have a look. With Gavin Gunning getting injured we are a bit short at the back to say the least."