Surprised Charlie Nicholas is adamant Celtic should have hijacked Scott McKenna's impending transfer to Nottingham Forest.
The Premiership champions had two bids for the Aberdeen star kicked into touch in 2018 but never returned and he is now closing in on a £3m switch to the Championship.
The Dons could eventually net a fee of £5m with add-ons and have a cast-iron 20 percent sell-on fee attached to the deal for McKenna.
But Nicholas believes his former side will regret allowing the 23-year-old and would have earned treble what they paid for in a couple of years.
Speaking in his Express column, he said: "At that sort of price range, Celtic should have moved for the Scotland international.
"They brought in another physical defender in Shane Duffy earlier this month, but they have only got him on loan for one season from Brighton and I don't think he's significantly better than McKenna.
"McKenna still has a fair bit to go before we can say he's good enough to compete with the best in Europe, but Celtic could have improved him.
"McKenna has a decent left foot which gives teams balance at centre-half. His physicality is strong and he can compete like Duffy.
"I don't understand why Celtic didn't consider trying to do a deal for the 23-year-old. If they were keen on him two years ago when Aston Villa had a £7m bid rejected then why not now when he can be bought for only £3m?
"They would have been able to develop McKenna and he could have enhanced his CV with trophies and cemented his place in the Scotland national team.
"By the time he turned 27 or 28 his value would have doubled, if not trebled."
