Danny Welbeck holds the key to Sir Alex Ferguson's hopes of signing Sunderland ace Jordan Henderson for Manchester United. England midfielder Henderson is one of United's top targets with Ferguson preparing a £15m bid either in January or at the end of the season. But he faces a battle with Manchester City, Chelsea and Liverpool for the highly-rated 20-year-old. United are understood to be his first choice, but Sunderland manager, Steve Bruce, will hold out for the best offer. Which is where Ferguson holds the upper hand. Reds striker Welbeck has been on loan at the Stadium of Light since the start of the season, impressing with a series of outstanding performances. Bruce is eager to make the move a permanent one but it remains to be seen if Ferguson would let go a player he expects to be an England international in years to come. Another option would be extending the 20-year-old's loan deal for a further 12 months as a sweetener to help secure Henderson. Bruce has made it clear he would love to sign Welbeck on a permanent basis. Danny is playing terrifically well at the moment and the Premier League is beginning to sit up and take notice, he said. I'm delighted for him because I think he's really finding his feet in the Premier League with us and his success is our success. But, in terms of converting any loan player to a permanent signing, you have to accept it's a fact of life that in most cases, the better they do the less chance you have of getting them. And the way that Danny is going, if he continues his progress, he'll be out of the reach of any but the very biggest clubs around. Ferguson has made his interest in Henderson known to Sunderland asking Bruce to keep him updated on the much-sought after star's situation. He is determined to test Sunderland's resolve with a bid, most likely in the summer. He can afford to let Welbeck extend his stay on Wearside with a wealth of attacking options already at Old Trafford. As well as Wayne Rooney, Dimitar Berbatov and Michael Owen, he also has the emerging talents of Javier Hernandez and Federico Macheda. Last summer he wanted to strengthen that further, trying to sign David Villa from Valencia and he continues to monitor Karim Benzema at Real Madrid. Would Welbeck for Henderson be a good swap for United? Have your say.