Following Manchester United's defeat to Atletico Madrid in the Champions League, Lisandro Martinez criticised the club for a lack of ambition in the transfer window, saying he expected more from Jason Wilcox.

Martinez's contract at United extends in the summer, although the club have the option to extend his contract for a further year. 

United are expected to revamp their defensive line in the summer, and it is unclear whether the club see Martinez in their long-term plans. The Argentine defender has had several long-term injuries during his time at Old Trafford, and his performances this season have not been at the required standard.

Despite his comments on Tuesday night, Martinez started for Michael Carrick's side against Leeds United on Sunday afternoon, but was taken off at half-time after picking up an injury.

United are reportedly looking for a replacement for Martinez. Speaking to Football Insider, former United chief scout Mick Brown said that the club are considering multiple options, but are looking for a player who has more 'consistency and command' in his game.

"There is every chance Martinez could be replaced, if not in January, then next summer, with a player who can bring a bit more consistency and command that back line," Brown said.

"So if they’re going to sign a new centre-back in January or even next summer, it wouldn’t surprise me if Martinez found himself out of the side.

"They're already considering their options behind the scenes, looking at potential options to come in and replace him, and doing their due diligence on a few different players.

"If the right player is there and could be available, then I expect they will make a move, and it should be Martinez who drops out to make way."

It was very clear that the summer was the perfect moment for United to sell Martinez, but the club failed to be proactive. He had a good World Cup, and given that United have the option to extend his deal for a further year, he had long enough left on his contract that United could have got a decent fee.

He has had injury issues, and United's current team doesn't suit a centre-back like him, especially if Harry Maguire is going to start regularly.

Carrick has opted to start Kobbie Mainoo next to Youri Tielemans in several games this season. While both players are technically excellent, neither is an elite athlete, and you therefore need athletes around them. The same goes for Andrey Santos.

Neither Martinez nor Maguire is an elite athlete, and they therefore should not be starting together, especially if Carlos Baleba is not playing in front of them.

Martinez is one of the best ball-playing defenders in the world, but from a defensive point of view, he is not reliable and makes too many errors. United's decision not to sign a central defender in the summer is bewildering.

Carrick does have several options in that position, but there is a clear lack of quality. Leny Yoro and Ayden Heaven have immense potential, but are still young. Maguire and Martinez are not good enough to be regular starters, and the same goes for Matthijs de Ligt, who has not played in nearly a year due to an injury.