Cardiff City lost out massively with Rotherham United deal - it's a real transfer blunder | OneFootball

Cardiff allowing Semi Ajayi to leave back in 2017 will always be a deal they look back at tinged with regret

Rewind eight years and Cardiff City were at the beginning of the Neil Warnock revolution, which resulted in promotion to the Premier League in 2017/18, but not everything he did within his time at Cardiff proved to be so successful.

On the pitch, Warnock got pretty much everything right, getting his side into the top flight despite carrying huge underdog status, although he was ultimately unsuccessful in keeping them there as they came back down at the first time of asking.

That remains the last time in which Cardiff played in the Premier League, with a series of on and off-field troubles since contributing to the fact they find themselves embroiled in a battle preserve their Championship status this season.

None of that can really be attributed to Warnock's time in South Wales, but there will be one particular thing he looks back on with huge regret from his time with the Bluebirds, and that's allowing Semi Ajayi to leave on a free transfer.

Semi Ajayi was an unknown quantity to Cardiff City

Ajayi had a decent pedigree in academy football, with Arsenal poaching him off Charlton after a successful trial in 2013, but as iso so often the case in youth football, he struggled to make the step up into the first team.

Cardiff City should've been the beneficiaries of Arsenal's blunder when he was recruited by Russell Slade in 2015, but even with the Bluebirds he struggled to make a meaningful impact, failing to make a single first-team appearance.

He spent time bouncing around on loan with AFC Wimbledon, Crewe and Rotherham, and it was for the Millers that he really made an impact, impressing enough in a loan spell that then-boss Paul Warne elected to make the move permanent.

It's understood that there was no fee involved in his move to Yorkshire, with Warnock sanctioning a move which had no financial return for Cardiff, largely due to the fact they didn't expect his career to follow the trajectory it did.

As it turned out, Cardiff were left with egg on their face as Ajayi was ultimately then sold by Rotherham for a fee of up to £2.5m just two years later to another Championship club, West Brom.

Cardiff City were left red-faced by letting Semi Ajayi leave

It wasn't too often in his career that Warnock got something so spectacularly wrong, but he did with this one, as Ajayi went on to have a stellar career with West Brom.

He played a starring role as the Baggies were promoted to the Premier League in 2019/20, scoring five goals along the way, in a season where Cardiff finished fifth and fell in the play-offs.

The Nigerian was a key member in the Premier League for West Brom too, although he couldn't help them avoid an instant return to the Championship, but having played 33/38 games that season, he came out of it with plenty of credit.

Although his time at The Hawthorns has since has been a little blighted by injury, West Brom have had a phenomenal service out of someone who cost them such a small fee and was at one point widely regarded as the best centre-half in the division.

It will surely sting Cardiff knowing they had that player in their ranks not too long ago and let him leave for no return, especially given their on-field struggles.

Letting Ajayi leave for free after seeing the career he went on to have really could make his departure one of the biggest transfer blunders in the history of the club, especially knowing that even at the tail end of his career, he'd still probably get into the Cardiff team.