All the latest news, views and transfer rumours from Old Trafford...
The 25-year-old was on the books of the Red Devils from 2005 until 2010, but he failed to make a single competitive appearance.
However, the Germany international goalkeeper, now at Hannover, has said that he looks back fondly on his time at United.
‘I really enjoyed a really great training in England, but never played for the first team [for Manchester United] in the Premier League’, Zieler told Goal.com. ‘But I don't know what will happen, it's hard to predict...
‘It's a fact I extended my contract with Hannover for another three years. For sure England is one of the countries that would be appealing - but it could also be that I will play for another 10 years in Germany...
‘I was very lucky that I already was allowed to play for one of the best clubs in the world, namely Manchester United’.
The former Everton midfielder, who had a season to forget in 2013-14, was a key player for United against Chelsea at Old Trafford in the Premier League on Sunday.
‘I think it’s a little bit too early but I do see signs’, The Manchester Evening News quotes Robson as saying. ‘I think Fellaini has been one of these players who’s come to Man United, and found it totally different to any other club.
‘The expectations, and the way United are expected to play football from the fans. The first season, he didn’t really find his feet, but I think he knows what it’s all about now and the last couple of performances have been very good.
‘He’s found where he is. He knows what’s expected now and he seems to have settled down and is playing the football he was playing for Everton’.