The 33-year-old, who reports said had fallen out with Mourinho, returned to the team for Tuesday’s 0-0 draw with Valencia in the Champions League.
After the game, he liked a picture of himself which had the caption: “It’s time for Mourinho to go.”
The Ecuadorian later wrote he liked the post “without reading the text”.
“These are not my views and I apologise for this,” the full-back said on Twitter. “I am fully supportive of the manager and my team-mates. We are all giving our everything to improve the results.”
Valencia, who joined United from Wigan in 2009, had missed United’s previous two games – their Carabao Cup exit to Derby, and 3-1 defeat by West Ham in the Premier League.
Following their fourth successive game without a win, midfielder Paul Pogba told reporters in the post-match mixed zone interview area that he had “been told I’m not allowed” to talk.
A clip of Pogba and Mourinho having a tense exchange on the training ground emerged last week, and the Portuguese has told the 25-year-old France international he will not captain the team again. Read more