The defender has been reprimanded following his public rebuke of the club’s leadership after their Champions League loss to Atletico Madrid.

Lisandro Martinez has issued a formal apology and received a club fine following his public criticism of Manchester United's leadership in the wake of their midweek European defeat.

The Argentine defender caused a stir on Tuesday after United fell to Atletico Madrid in the Champions League, claiming head coach Michael Carrick had not been provided with a squad capable of competing at the highest level.

Martinez specifically pointed toward recruitment and called for more backing from technical director Jason Wilcox.

Following clear-the-air discussions with Carrick and senior executives on Thursday, the 28-year-old took to social media to express regret over the public nature of his comments.

"Today I met with the club's leadership and the manager," Martinez stated. "It was a very positive conversation, where we were able to exchange views and speak openly about what happened after Tuesday's game."

"Everyone knows that I am a passionate person and that I live football with great intensity. The frustration of the defeat led me to express how I felt at a time and place that perhaps were not the right ones, and for that I want to apologise."

Lisandro Martinez of Manchester United. Image: Imago

Despite clearing the air, club officials moved to discipline the centre-back with a financial penalty for breaching internal conduct standards.

The controversy comes at a turbulent moment for Carrick's side. Manchester United sit 13th in the Premier League table with just six points from six fixtures, having managed only two victories across nine matches in all competitions this term.

The turmoil prompted criticism from former club captain Roy Keane, who described the ongoing drama at Old Trafford as "a bit of a circus" during an appearance on The Overlap podcast.

Martinez sought to draw a line under the episode, insisting the squad is pulling in the same direction ahead of Sunday's trip to Elland Road to face Leeds United.

"Our club is at its best when we are all united, and I recognise that my words in that moment did not help with that," Martinez added. "With this situation now behind us, we are fully focused on winning together."

While the disciplinary matter has been addressed internally, questions linger regarding Martinez's long-term standing at the club. Carrick is scheduled to address the media on Friday, where he will likely face questions on whether the defender will feature at Leeds.

Martinez's existing deal runs out at the end of the current campaign. Although Manchester United hold a club option to trigger a 12-month extension, management has yet to determine whether they will activate the clause.