Mastantuono cost Real Madrid a record fee, and he is spending next season in Florence

Real Madrid and Fiorentina confirmed this week that Franco Mastantuono is going to Serie A on loan until 30 June 2027. Madrid’s official statement is two lines long and says nothing about a purchase option, which is the point. This is not a sale. It is a club moving a player they paid a record fee for out of the building for a year, twelve months after he arrived, while keeping every right they had over him.

The most expensive player ever sold out of Argentina

Madrid agreed 45 million euros with River Plate in June 2025, beating Paris Saint-Germain to him, and structured the money across three instalments: 20 million net up front, 12.5 million in June 2026 and another 12.5 million in June 2027. River’s own accounts later put the total cost at 63.2 million euros once everything was added in, the highest fee ever paid for a player from the Argentine league. He signed a six-year contract and formally joined on 14 August 2025, his eighteenth birthday.

Now read that payment schedule against this week’s news. Madrid still owe River a 12.5 million euro instalment next June for a player who will spend that entire season on a Fiorentina team sheet. Clubs do this constantly and nobody should pretend otherwise. It is still a clean way of measuring how the first year went against what was budgeted for it.

One league goal, and a record that had nothing to do with output

He was not ignored, which is the part people will get wrong. Mastantuono came on for Brahim Diaz in the 68th minute against Osasuna five days after signing, and by matchday two he was starting against Real Oviedo at 18 years and 10 days old, the youngest player to start a La Liga game for Madrid since 2005. He took that mark off Endrick, who had held it for barely a season.

Then the year happened. He made 35 appearances across all competitions and scored three times. In La Liga specifically he finished with 1,037 minutes, one goal and no assists, and his minutes thinned out as the season wore on rather than building. Argentina left him out of their World Cup squad.

Some of that is on him and some of it is not. The coach who picked him for the Oviedo start was Xabi Alonso, and Alonso was sacked on 12 January, seven months into the job, with Alvaro Arbeloa promoted from the Castilla dugout to replace him. An 18-year-old import in a squad that changes managers in January is not in a setting anyone develops well in.

There was never going to be room this season

The other problem is arithmetic. Real Madrid announced on Thursday that Vinicius Junior has extended to June 2032, six more years, ending a summer of Arsenal interest that never produced a bid. Whatever Madrid’s front line looks like in October, one of the shirts Mastantuono needs is now spoken for until he is 24.

So the loan is logical from Madrid’s side. He turns 19 on 14 August. A season of starts somewhere serious is worth more to them than another year of 20-minute cameos, and with no purchase clause announced, they can simply take him back when the maths changes.

Fiorentina finished 15th

Where he has been sent deserves more scrutiny than it will get. Fiorentina came 15th in Serie A last season, changed manager in November when Paolo Vanoli took over, and begin this campaign under Fabio Grosso. Nobody would call that a settled environment.

What it does offer is minutes, and probably a lot of them. A club finishing 15th needs a teenager who cost somebody else 45 million euros to play every week, and that is the entire trade here. If it works, Madrid get back a 20-year-old with a full season of Serie A starts behind him and an instalment plan that has finally run out. If it does not, they are left asking a harder question about what they actually bought in June 2025.

For Mastantuono the calculation is simpler than it is for either club. He has already missed one World Cup squad. Playing badly in Florence is still worth more to him than not playing at all in Madrid.

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