OXFORD United have sold a centre back for a seven-figure fee in each of the last three summers.

Rob Dickie, Rob Atkinson and now Luke McNally are among a group of just 12 players in U’s history to leave for more than £1million.

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None of them made a single Sky Bet League One appearance before joining United – Dickie played 45 minutes of Reading’s final Sky Bet Championship game of the 2015/16 season – but they were all sold for a hefty profit.

The U’s stand to gain from more than just the transfer fees, though.

It is understood that United inserted a sell-on clause in the deal that took McNally to Burnley, among other add-ons. The exact percentage is unknown.

They did the same when Atkinson moved to Bristol City 12 months ago, while Karl Robinson has openly said the club negotiated hard on the sell-on percentage when Dickie joined Queens Park Rangers in 2020.

“I’ve seen players from this level step up before and I had true confidence that he could probably go again,” the U’s head coach told the Oxford Mail last August.

“That’s why when we were negotiating one of the sticking points was the sell-on clause, because we believe the kid has got that potential.”

Dickie has been linked with several Premier League clubs in the past 12 months and, with two years left on his QPR contract, would surely command a sizeable fee – earning the U’s a cash boost.

It goes both ways, though, as United’s last two big-money departures demonstrate.

Eastleigh are understood to have inserted a sell-on clause when they sold Atkinson to United in January 2020.

It meant they were due a slice of the fee when Bristol City paid somewhere in the region of £1.6m, plus add-ons, to sign the centre back from the U's last July.

There are also unconfirmed reports that St Patrick’s Athletic, who sold McNally to United, will benefit from a sell-on clause.

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The two clubs obviously saw their respective players had the potential to go higher than League One, and so it proved. Both left the U’s after just one Football League season, less than 12 months after making their debuts.

Of course, add-ons do not guarantee money down the line. Only last week we revealed United had missed out on a cash boost from Joe Rothwell’s Blackburn Rovers departure.

The U’s inserted a sell-on clause when the midfielder left for Ewood Park in 2018, but he ran down his contract and joined AFC Bournemouth as a free agent so there was no money to gain.

United will hope history does not repeat itself, but there is a good chance at least one of Dickie, Atkinson or McNally will climb another level in the coming years.

Now, the U’s need to find the next centre back on the production line. James Golding is highly-rated but, at 17, is surely at least a couple of seasons away from playing regularly in League One.

It means we may not see another seven-figure departure next summer, but that is not the priority right now: United must find one, maybe two, defenders who can hit the ground running when the season starts in just 31 days’ time.