But despite Mourinho's public assertion that De Gea will remain at Old Trafford, concern over the Spaniard's intentions have now prompted United to intensify their monitoring of Oblak, with the club increasing their scouting trips to the Vicente Calderon to watch the 24-year-old.
Man Utd are seemingly planning for life without David De Gea as reports claim that they're interested in Atletico Madrid's Jan Oblak, or Benfica goalkeeper Ederson.
De Gea has been a regular fixture in the Manchester United team under Jose Mourinho this season and has helped the Red Devils win the EFL Cup this term.
I would want, at the very least, United's best player for at least two of the last three seasons sitting beside me in case I needed him.
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The 30-year-old, who saved a penalty in United's draw with Southampton on Wednesday, said: "For me, it's very important to be playing".
This time around though it looks as if De Gea's wishes will come true as he remains a top priority for Real and ambitious president Florentino Perez.
Losing De Gea would be a big disappointment for United fans but bringing in Oblak as his replacement would certainly ease the blow as I think he'd be a superb signing if they could pull it off.
Smalling has started only 12 Premier League games because of foot and knee injuries this season, but Mourinho has questioned the 27-year-old's dedication to the club, suggesting that he should play through the pain barrier.
With Atletli, he has garnered experience at an even higher level and played in last year's UEFA Champions League final.