It's no secret that Wayne Rooney has had a forgettable 2016 so far which, at this rate, is showing no signs of improving.
The England captain was dropped by Gareth Southgate for the Three Lions' Tuesday night qualifier away to Slovenia and has been absent for the past three games from Manchester United's starting XI.
But that is set to become four matches on the bounce that the Red Devils captain has not featured from the start for Mourinho's men, and the 30-year-old will no doubt dread warming up on the touchline at Anfield on Monday evening.
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Liverpool host United in the biggest game of this week's fixtures, with the Reds currently boasting a three-point advantage and sitting two places higher than their rivals.
However, should Rooney feature against Liverpool, Reds boss Jurgen Klopp will not be resting on his laurels and has warned his players to be on high alert if the United captain does feature - regardless of his current form.
In his pre-match press conference, per The Mirror, Klopp said: "Rooney is a goal scorer and a threat. A situation like this can happen in a long career. From my side he's a world class player."
But, perhaps in attempt to stay in the Liverpool fans' good books, the German jokingly added: "I am manager as Liverpool FC so I know it is not allowed to like United players!"
Mourinho has favoured Juan Mata - who was sold to United by the Portuguese during his days in charge at Chelsea - ahead of Rooney in recent matches, with the captain having scored just once for the Red Devils this season.
And considering there were question marks over the Spain midfielder's future at Old Trafford when Mourinho first arrived, it proves how far down the pecking order Rooney is continuing to fall.
However, Rooney will be boosted by the fact that his single goal at Anfield last season was enough to take all three points back to Old Trafford. But with Klopp enjoying a fine start to the new campaign with the Reds, he will be hoping to inflict revenge.
It would be the perfect time for the England international to find some form in a big game against a team he would loath to see win - considering his allegiance to the Blue side of Merseyside.
But it remains to be seen if Mourinho will be bold enough to introduce an out-of-form Rooney in one of United's biggest games of the season.
Is Wayne Rooney still capable of having an impact on Manchester United's biggest games? Have your say in the comment box below.