Lingard has completed a move to Nottingham Forest on a one-year contract rumoured to be worth around £200,000 per week.
West Ham also pushed to sign him and were prepared to make him their best-paid player through a contract worth £150,000 per week, but Forest hijacked that move.
Keys pointed out that Lingard was an average player for a Manchester United side who were not as good as teams of yesteryears.
He is intrigued to see how he does in a newly-promoted Nottingham Forest side but conceded that he is still surprised that the 29-year-old rejected a move to the London Stadium.
Keys took to Twitter and wrote: “Jesse Lingard is ‘bang ordinary’ to occasionally ‘good’ in a decent team – which United are not and he couldn’t get a starting place there.
“It’ll be interesting to see how he goes in a struggling side.
“How on earth can he choose Forest over West Ham?”
Lingard has some convincing to do in order to justify his wage package in the Nottingham Forest squad, where he is by far the best-paid player.
He also had offers from the MLS and Saudi Arabia but the attacking midfielder decided to stay in the Premier League.
