Alli's future at Spurs has been the subject of much speculation since he was substituted at half-time during the 1-0 defeat against Everton on the opening weekend of the new season.
The England international was subsequently dropped from Mourinho's squad for a Europa League qualifying meeting with Lokomotiv Plovdiv, and has made just two starts and three substitute appearances in all competitions since.
There were rumours suggesting French champions PSG were interested in signing Alli before the transfer deadline earlier this month, but no deal materialised.
Despite finding himself out of the side, Mourinho has praised Alli for his professional attitude in training and hinted that he could still have a long-term future at the club.
The former MK Dons youngster was given a rare chance to impress when he was named in the starting XI for Thursday’s Europa League clash away at Royal Antwerp.
Speaking ahead of kick-off, Mourinho once again praised Alli’s attitude and application, while saying his lack of regular action is simply down to the intense competition for places.
"Dele is working hard and I feel very hurt when I don't select him or even don't have him on the bench, but this is the consequence of the attacking players we have," Mourinho told BT Sport.
"Tonight [Dele and Steven Bergwijn] have to catch the opportunity with both hands.”
Alli was one of nine changes to the Tottenham side from Monday’s win at Burnley, with Gareth Bale also handed a start while free-scoring duo Harry Kane and Son Heung-Min dropped to the bench.
However, Alli was one of four players taken of at half-time as Spurs trailed the Belgian outfit at the break, with Mourinho's side eventually falling to Antwerp in a 1-0 defeat.
Mourinho accepts it is a challenge trying to keep so many players happy, but admits it is a nice problem to have.
"I am happy. I have lots of good players and everyone is motivated,” he added. “Everyone wants to give everything on the pitch.
“They show frustration when they are not playing in the right way when they are on the pitch.
“You could say it is a risk to change so many players but I would say I accept the risk because I trust the players and the squad.”