Jamie Carragher believes Lisandro Martinez is a "worry" for Manchester United fans.

Carragher predicted that Martinez would be a flop in the Premier League due to his diminutive stature but he enjoyed a tremendous first season after signing from Ajax.

Martinez's second year in Manchester was disrupted by injuries and supporters have started to question his performances in 2024/25 as he's looked a shade of the player he was.

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The centre-back has failed to produce the level of displays that he did during his debut campaign with United and made a mistake that directly led to a Tottenham goal in the quarter-final of the Carabao Cup, while his defending for Dominic Solanke's second goal was dubious.

Martinez's form is beginning to become a problem and Carragher believes he hasn't looked comfortable since playing in the back-three system, which Ruben Amorim has implemented.

"I think a worry for United fans is Lisandro Martinez. I didn't think he'd play well in a back four because he's small, but he had a really good first season," Carragher said on Sky Sports.

"In some ways you'd think he'd be suited to a back three, he can step out on his left foot and he's got two big defenders next to him. But I don't think he's looked as comfortable since Amorim came in. He had a really poor night."

Speaking in May 2023, Carragher apologised for his original prediction on Martinez and said: "That’s not about Martinez [being too short for the league], that’s about any centre-back coming to the Premier League who is well under six foot you think is going to have a problem.

"But he hasn’t and every player has weaknesses whatever that may be, whether it’s physically or technically, and the best players hide the weaknesses, nobody’s a perfect player. I just looked at him and thought, 'how can you overcome that in the Premier League?'.

"I wasn’t the tallest centre-back and I used to go into games worried that I’m going to get found out and bullied. At times you lose big challenges and goals. I thought he’s two or three inches shorter than me.

"But just like with Casemiro, it’s a massive drop off when Martinez is not in the Manchester United team defensively but also his ability on the ball and playing out from the back.

"He’s a warrior, he’s a leader and when you think of that spine of the team certainly him and Casemiro, two new signings, they’ve made a huge difference. So apologies Lisandro and all Man United fans can you stop tweeting me about Lisandro Martinez now please!"

United paid £46.8million, rising to £55.3m, to Ajax for Martinez in the summer of 2022.