He missed United's open training session today and, though he did apparently train later on, Mourinho doesn't know whether he'll make it back in time.
"There wouldn't be many United supporters before saying there's an outstanding chance of us winning the Champions League, but when you sign somebody like him it can be the turning point in your season in the biggest competition there is".
Marcus Rashford's first-half brace proved the difference as United increased their stranglehold on second spot in the Premier League and got a key week off to a flying start, with the FA Cup quarter-final against Brighton following Sevilla's visit.
It was seen as a missed opportunity for Sevilla, given they controlled much of the game and saw Luis Muriel denied a goal by a remarkable David de Gea save just before half-time. "I imagine that if we lose against Sevilla everyone will have forgotten what we did in the last couple of weeks".
The La Liga side have failed in their three previous attempts to progress from the competition's last-16, including falling at this stage against Leicester last season.
Sevilla's best achievement at the UEFA Champions League was in the 1958 season when they reached the quarter finals but lost to Real Madrid 10-2 on aggregate. He will look to put in a similar performance in this game as well.
"We are a strong team once we take the lead". "Alexis played Champions League for a few years with different clubs, at least one club that is feeling the responsibility to win it when he was at Barcelona".
Mourinho-managed teams, too, are hard to beat when they are ahead - a fact highlighted by a prolific Liverpool side's struggles to break down United after the Portuguese set his side up defensively in the second period following Marcus Rashford's two-goal salvo in the first 24 minutes.
"I do not have many options for right-back".
Rashford also insisted that he didn't need to be reassured by his manager when he was struggling for playing time, saying: "He doesn't have to (speak to me)". "In modern football, you have to live day-by-day, week-by week and match-by-match".
"They didn't use some chances also but, in the end, the most important thing is three points".