Beale’s side had to face disappointment at Hampden Park on Sunday when Celtic beat them 2-1 to win the Scottish League Cup.
It was Beale’s first defeat since taking charge of Rangers in December and he failed to add the first trophy to his cabinet in his managerial career.
The Rangers boss went with John Lundstram and Glen Kamara in the middle of the park from the start despite Raskin’s performances since joining Rangers towards the end of last month.
Ferguson admitted that the Belgian has been impressive since arriving and is the kind of player Rangers have been looking for.
He insisted that there is little to choose between the options Beale had but conceded that not playing the January signing in the starting eleven might have been a mistake from the Rangers boss.
The former Rangers captain said on the Go Radio Football Show: “I was surprised by watching Raskin in the last couple of weeks, certainly last week against Livingston.
“I thought he was a stick-on to play and I was surprised but not disappointed.
“If you see the four who can play in that holding two – Lundstram, Raskin, Jack and Kamara – I would have been happy with any of the four of them.
“I did think from his performance last week, he is the type of player Rangers have been needing and so I was surprised.
“And maybe Michael Beale would be looking back on it and maybe that was a mistake that he made.”
Rangers will have to refocus on the league when they host Kilmarnock at Ibrox next Saturday.
