West Ham United boss Sam Allardyce says former Manchester United manager Sir Alex Ferguson always believed Ravel Morrison would fulfil his potential.

Morrison has enjoyed his breakthrough season in the Premier League while also staring for the England Under-21's, raising hopes he could travel to the 2014 World Cup in Brazil next summer.

After a chequered career at United, Morrison has flourished under Allardyce at West Ham having been offloaded by Ferguson, something which the Scot predicted.

"Sir Alex [Ferguson] let Ravel go for his own benefit," Allardyce said ahead of West Ham's trip to United on Saturday. "He [Ferguson] said that if he comes down to you, hopefully he will find a new life and a new way of living.

"His ability will then start to come through because all he asks and all he wants in his life is to play first-team football, that was all he said he wanted to do and why he wanted to leave.

"In actual fact, he struggled to look like he was capable of playing football in the first team with us. That's why we sent him on loan to Birmingham and I thought since that year, he's grown up.

"Somewhere along the line, the lad has woken up and I think he's changed himself and delivered."

Despite Roy Hodgson stating new faces an unlikely to be included in his England World Cup squad, Morrison's performances have caught the eye this season and upon West ham's visit to United, he will looking to give his former side a taste of what they're missing.

"The expectation becomes 'will it come every single week?' and that can't really happen at such a young age," Allardyce added.

"It's nice if it does. We've got to manage the situation and just try and keep encouraging him.

"I think from our point of view, if he gets selected for Old Trafford on Saturday, that the real message from me to him would be to try and get a result as a team and play one of your top performances in a team situation when you would help to get us that result by using your abilities in a team performance.

"When you've got his ability, there is going to be the temptation to go out and think 'look at me' - and I have to try and guard and avoid that situation."