Dele remains sidelined for our Premier League encounter at Bournemouth on Thursday evening (9 July, 6pm).
The attacking midfielder missed Monday's win against Everton with a hamstring issue.
Speaking after training on Wednesday, Jose Mourinho was asked how serious the injury was, and replied: "It's small, but he's not ready for tomorrow. You know that he has a little history about his hamstring, so he has to be careful, and not risk it when you know that he has a little problem there.
"There are no further concerns, nothing from the last game."
Eric Dier is now suspended, with Japhet Tanganga and Juan Foyth also out.