From nowhere to Carrick's teamsheet: can Diego Leon solve Man Utd's left-back crisis?

It was a mix-and-match group of players that Michael Carrick fielded against Lausanne-Sport on Friday, but one name stood out. Diego Leon, the 19-year-old Paraguayan left-back, came from nowhere to play his first minutes under Carrick.

With senior stars on international duty and the best academy prospects away with their countries, Carrick was restricted in his options. United won 2-1. But the real story was Leon's inclusion, and what it says about the club's left-back crisis.

Who is Diego Leon?

There was plenty of excitement when Leon arrived at Old Trafford in the summer of 2025 for an initial £3.3 million, potentially rising to £7 million. Arsenal and Manchester City were also keen. He had played 33 first-team games for Club Cerro Porteno before turning 18, and his rapid speed and bravery going forward marked him as one of the most thrilling young prospects in South America.

He was part of Paraguay's provisional World Cup squad this summer before failing to make the final 26.

What has gone wrong?

Leon was unveiled alongside Bryan Mbeumo, Matheus Cunha and Benjamin Sesko last season and made matchday squads against Manchester City, Brentford and Sunderland early on. He was also on the bench for the Carabao Cup defeat at Grimsby.

Then he vanished. He did not make a single first-team squad for the rest of the season. He made 17 starts for the Under-21s and played two EFL Trophy games, but was barely glimpsed in pre-season this summer as Harry Amass stepped up to compete with Luke Shaw.

This season, he has not played a single minute in three Premier League 2 games. Amass is starting ahead of him for the Under-21s.

Why does this matter?

United failed to sign a left-back in the summer window despite it being a priority from the start. Shaw is the only natural option in the senior squad. Dorgu has been used further forward. Amass could have left on a permanent deal to Burnley but the £3.5 million offer was not enough.

Leon's challenge is to get regular Under-21s minutes first, but impressing Carrick in Friday's friendly and in training at Carrington is an opportunity he could do with taking.