Alli withdrew from the Three Lions squad on Monday ahead of the game with Switzerland after picking up an injury in Saturday’s defeat to Spain.
But Southgate believes the 22-year-old will make Spurs’ Saturday lunchtime kick-off with Liverpool.
Southgate said at his press conference: “He has just had a minor strain and should be fine for his club at the weekend I would think, but tomorrow’s game will come too quickly.”
Alli played 90 minutes at Wembley on Saturday and Southgate was impressed with the Tottenham player’s contribution.
The manager added: “I thought his performance was good, in terms of his retention of the ball I thought he was improved in that area, his work without the ball has been good over the last six months with us.
“He makes critical forward runs, like everybody else we learned a lot from the game.”
Southgate, who led England to their best World Cup finish since 1990 in the summer, was keen to avoid talk of a new contract.
“We have had initial discussions as I said, that has been it,” he said.
“For me I have to focus on the job in hand. I am contracted for the next 22 months and my focus is on tomorrow night and then building this team to be as competitive as it can be.
“This summer was an incredible experience for everybody, so they are the games that everyone wants to be involved in, beyond that I don’t want to get into details because that will be a distraction ahead of the game.”
Despite their impressive summer performance, the Three Lions go into Tuesday’s game against the Swiss aiming to avoid four successive defeats for the first time in their history following losses against Croatia, Belgium and Spain.
Southgate is not concerned about that record, however.
“Not many England sides have played a World Cup semi-final and third-placed play-off so these stats can be whatever you want them to be really,” he added.
“From our point of view we don’t want to be in the habit of losing matches but to play three teams of the quality we have in the last three matches is a very rare occurrence in international football so we have to focus on our performances, and improving as a team.
“We have got to keep focused on the things we can control.”
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