How Middlesbrough and Huddersfield Town are both transfer losers right now - thanks to Chelsea | OneFootball

Leo Castledine was red hot at Huddersfield Town and was then sold by Chelsea to Middlesbrough, where he's failed to make an impact

There arguably wasn't a more exciting talent in the first half of the 2025/26 campaign than Chelsea loanee Leo Castledine.

The 20-year-old had struggled in his first loan spell away from Stamford Bridge the season prior at Shrewsbury Town, contributing little as Salop were relegated to League Two, but he still showed enough promise to warrant Huddersfield Town bringing him in this summer.

And at the Accu Stadium under Lee Grant, he had a breakout half-year. A goal and three assists in the Vertu Trophy demolition of Newcastle United's under-21s served as a boost to the starting eleven for league games, and he never let go of that spot.

In his final 10 league games for the Terriers, he scored eight and assisted one. Those goals were evenly spread out, too, as he failed to get on the score sheet in just three of those games.

It was evident that the young attacking midfielder was a class above the rest, and Chelsea saw an opportunity to make some money on their academy graduate, as they recalled him in January to sell him to Championship promotion challengers Middlesbrough for a little under £1 million.

He has failed to kick on at the Riverside, though, and with Huddersfield falling out of the play-off race since Castledine left, it could perhaps go down as one of the most disappointing signings of the season.

Leo Castledine's stop/start beginning of his Middlesbrough career

To call Castledine's move to Middlesbrough a flop already could be rather harsh, as the 20-year-old has battled through various injuries already throughout his time at the Riverside, which has stopped him from making any real inroads into the team.

After his first and, to this date, only start for the club in a 4-0 win over Preston North End in late January, a leg muscle injury took him out of action for over a month.

The packed schedule in the latter stages of the season meant he had fewer training sessions to build up to full fitness, and despite scoring his first goal for the club off the bench in a draw against Bristol City, that wouldn't shoot him back into the starting eleven.

Another period on the sidelines followed in April, and he returned for the final two games of the regular season and in both play-off semi-final legs against Southampton, failing to score in any of them.

You'd imagine that pre-season will do him the world of good as he gears up for a first full year in the Championship, but given the amount of hype that surrounded him in January, plus the fact that he came in to help Boro over the line in their pursuit of the top two and had a limited impact in doing so, means that right now, the transfer is a slight failure.

Huddersfield Town will have looked on in disappointment at Leo Castledine's Middlesbrough start as their own season faded away

After Castledine's final game for Huddersfield, a 2-2 draw against Exeter City on January 4, the Terriers were fourth in League One. They were still nine points removed from the automatic promotion spots, but they were at least in the thick of the play-off hunt.

Huddersfield were ultimately never able to replace the 20-year-old after he left, though. Lee Grant was sacked a couple of weeks later, and his replacement, Liam Manning, had to scramble to sign players in the final weeks of the transfer window who couldn't fill the goalscoring role left by the Chelsea loanee.

Castledine ended the season as the Terriers' top scorer in League One, netting 10 in the first half of the season. The lack of a goalscoring threat outside of him saw Huddersfield slump down the table.

After the 20-year-old left, they placed 15th in the second half of the season, and they ended the campaign eight points adrift of Stevenage, who occupied the final place in the top six.

Ultimately, Huddersfield's problems in 2026 stemmed further than just Castledine's departure, but that almost kick-started their downward spiral, and plenty of 'what if's' have been floated around regarding what the end of their campaign would have looked like if their top scorer had stayed for the whole year.

In the end, both Middlesbrough and Huddersfield endured poor ends to the campaign, and things may have been different if Boro had targeted someone with a more veteran instinct in a promotion race in the Championship, or if the Terriers had kept their star man for the whole year.