Alex McLeish has questioned why West Ham chiefs have allowed rising star Grady Diangana to join West Brom.

Speaking exclusively to Football Insider, the experienced manager suggested there would have been extensive talks among manager David Moyes and the board before the sale of the winger was sanctioned.

West Brom announced earlier this month they had signed Diangana after his successful loan spell when they were in the Championship last season.

The fee was not announced but the 22-year-old is believed to have cost £18million including potential add-ons.

Former Aston Villa, Scotland and Rangers manager McLeish believes Diangana was sold either because Moyes does not think he is good enough to be a future Premier League star, or West Ham are seriously short of cash.

It is a deal that left West Ham supporters fuming and even led to player protests on social media led by skipper Mark Noble.

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“What’s going on behind the scenes? It’s maybe a different matter to what supporters are seeing,” McLeish told Football Insider. “They would have had big discussions about it and they probably realised that maybe supporters won’t like this but we have to be ready with an explanation why we’re doing it and maybe they just don’t see him fitting in to the bigger picture.

“I’m sure they’ll be kicking themselves if the guy goes on to even bigger things but sometimes you have to balance the books, of course.

“You also have to think, ‘is he going to be at the level that we want to go to’?

“David Moyes is thinking, ‘if West Ham have to go to another level then possibly he’s come up short’.

“Or, it’s to do with the balancing of the books. In order for Moyesy to bring other wages in and a more experienced set of players”.

In other West Ham news, Football Insider has been told Sullivan and Brady are ‘losing touch with reality’ amid Guardian takeover update.