Manchester United duo Luke Shaw and Fred will find themselves walking a disciplinary tightrope if they recover from their respective injuries in time to face Chelsea on Sunday afternoon at Stamford Bridge.
Shaw, who has provided two assists in 15 appearances for United this season, is in danger of missing the trip to west London after suffering a second concussion injury in as many games against Watford last weekend.
The left-back, who was forced to miss England's two fixtures over the recent international break as a result of the blow to the head he suffered in the 2-0 defeat to Manchester City, was forced off inside the final 10 minutes against Watford last weekend, also missing Tuesday's trip to Villarreal in the Champions League.
Speaking on Friday during his pre-match press conference, caretaker boss Michael Carrick hinted that a late call would be made on the availability of the former Southampton man.
"Luke took a bang on the head and was concussed three weeks ago and he took a bang against Watford," said Carrick. "We assessed him during the week and will make a call on how he is."
Should Shaw get the green light to be involved at Stamford Bridge, he will have to watch himself as he currently has four yellow cards attached to his name in the Premier League so far this season.
The same, too, can be said of midfield enforcer Fred.
The Brazilian, who has faced a torrent of criticism from supporters this season, is also just one booking away from being forced to serve a one-match ban.
Like Shaw, it remains to be seen if Fred will be involved against Thomas Tuchel's side after twisting his ankle against Villarreal. He managed to continue playing on through the pain, but it remains to be seen if he will be available.
Carrick said: "Fred twisted his ankle the other night, he managed to carry on, which was pretty incredible, to be honest, seeing the game out and playing a big part in winning the game for us.
"We'll have to see how that settles down."
The yellow card system does not reset itself until matchday 19 of the Premier League campaign has been concluded, meaning those in immediate danger of being suspended will have to watch themselves until the conclusion of the Boxing Day and December 27 fixtures are completed.
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