Spurs signed highly-rated left-back Reguilon from Real Madrid alongside the returning Bale, with the Welshman returning on a season-long loan with an option for a second year.
While Bale, who has a knee injury, will not be fit until next month, Mourinho hopes to have the 23-year-old Reguilon available for selection later this week.
“You ask me about Sergio and I think Sergio will be quite quick. He is in the best period of his recovery,” said the Spurs boss.
“He’s training today (on Sunday while Spurs played at Southampton) with one of my assistants. He cannot play on Tuesday but I would say he will be available for us maybe for the end of the week.”
Mourinho was reluctant to pinpoint an exact return date for Bale.
“I don’t know when Gareth can be back. The only thing I know is that his motivation is high,” he said.
“He’s so happy to be with the club of his heart, he’s so happy to play for us. And when a player has this motivation, many times you can shorten the period of recovery, you can shorten the period of getting fit and ready to play.
“We want to help him so when he’s available to train with the team, we’re more than happy to have him and help him back to a level that made him one of the best players in the world.”
On Tuesday, Tottenham travel to nearby Leyton Orient in the Carabao Cup third round and Mourinho named many of the players who will take part for the north London side.
“Some positions in the squad give us incredible options. If you look to our bench [at Southampton] you can imagine that Aurier is going to play, Joe Hart is going to play, Moussa is going to play, Toby,” he said.
“Lamela is going to play so you can imagine that some of these guys are going to play, replacing players from the same level. Exactly players from the same level so you can imagine some of them are going to play and replace the others.”
The game will be a special one for Harry Kane, who helped out his first loan club Orient by sponsoring their shirts this season, boosting the club with vital funds and also supporting good causes.
As part of his deal, Orient’s home shirt carries a message of thanks to frontline workers tackling the coronavirus pandemic.
Mental health charity Mind and Haven House Children’s Hospice have their logos on Orient’s two other shirts as part of the deal.
Mourinho suggested that Kane could play against his former loan club on Tuesday night if he felt able to.
“Yeah, Harry in principle he has to be. We need him, especially in these matches against these teams who are seen in theory as inferior and inferior teams are going to defend against you and you need a striker,” said the head coach.
“I want Harry to play. That’s if he feels he can, if he feels ready to do it. He’s an experienced player and he knows his body better than any of the sports science guys or any medical guy and if he’s ready to play it’s possible.”