Lisandro Martínez was shown a red card against Leeds United for violent conduct, the game after Harry Maguire was dismissed against AFC Bournemouth.
Since Michael Carrick replaced Rúben Amorim in January, Harry Maguire and Lisandro Martínez have been an impressive duo at the heart of Manchester United's defence.
Martínez was injured in the days after United's 1-1 draw against West Ham United at the start of February, putting him out until United's trip to the Republic of Ireland for a three-day training camp during the 24 days between the Bournemouth game and the Leeds United tie.
Harry Maguire was dismissed against AFC Bournemouth before the break for a shirt pull in the penalty area, resulting in a second yellow card. His absence meant Martínez's return was even more important for Michael Carrick, but his red card against Leeds United has only caused more concern.
Maguire handed another match ban
Maguire's red card was initially a one-match ban, meaning he would miss the Leeds United tie at Old Trafford, but would return in time to face Chelsea away from home this weekend.
However, Laurie Whitwell of The Athletic has now reported that Maguire's actions towards the fourth official on his way off the pitch have led to another match ban.
He was officially charged on April 1, with The FA saying: "It is alleged that the defender acted in an improper manner and/or abusive and/or insulting words and/or behaviour towards the fourth official following his dismissal."
Maguire's absence will be seriously felt, with Martínez also suspended for the trip to Stamford Bridge on Saturday evening.
United to appeal Martínez ban
United are appealing the Martínez ban, claiming that it was not "violent conduct", as he was challenging for the ball and did not use force.
However, referees told Premier League clubs at the start of the season that hair pulls would result in a straight red card, and the PGMO are said to be confident that the rules have been correctly applied.
Former United academy defender Michael Keane was sent off earlier this season for a hair pull on Wolves forward Tolu Arokodare, which led Howard Webb - head of the PGMO - to explain their stance on hair pulling.
"It is in the guidance we give to clubs before the season starts, the book that the Premier League produces, that grabbing someone’s hair with force is deemed as violent conduct and a player will be sent off," he said.
This leaves Michael Carrick just Ayden Heaven and Leny Yoro as first-team central defenders to choose from. Tyler Fredricson would have been in line for a call-up if it hadn't been for his injury in the Premier League International Cup quarter-final against Real Madrid.
Sonny Aljofree, Louis Jackson and Godwill Kukonki are the most likely young defenders who could join the first team this weekend.