Lindelof has not featured for the Red Devils since being replaced at the interval of their pre-season friendly with Liverpool at the end of their tour of the United States.
The Sweden international was not in the squad against either Manchester City or Fulham in the Community Shield and Premier League respectively, and there has been a host of speculation surrounding his future this summer.
However, it is thought that Lindelof will see out the final year of his contract at Old Trafford before leaving on a free transfer next summer.
The centre-back was recently pictured on crutches in one of his wife's social media posts, and Ten Hag has now revealed that an issue with his toe is preventing the Swede from being available.
Lindelof is out of action with a toe injury
Man United will also again be missing Leny Yoro, Tyrell Malacia, Luke Shaw and Rasmus Hojlund for Saturday's game against Brighton, but Harry Maguire is set to be available despite an injury scare against Fulham.
"There is no confusion [about Lindelof], he has an issue on his toe," Ten Hag told reporters during his press conference on Thursday afternoon.
"So hopefully he can return quickly, but he is not available for the weekend. Whereas also we have some more [issues], Tyrell Malacia, Rasmus Hojlund. They are not available as well. Luke Shaw, of course."
Another player who will also not feature this weekend is Facundo Pellistri, with the Uruguay international completing a permanent switch to Panathinaikos on Wednesday, and Ten Hag said that the attacker "needs games to improve and progress".
Ten Hag hails Pellistri after Man United exit is confirmed
"He's a very talented player, progressed very good last year, but we have a lot of competition in wide areas. We look at what we need as a squad but every player needs a perspective and in this moment we had many players to compete in these positions," said the manager.
"We couldn't give him the right perspective but he has high potential and he needs games to improve and progress. He gets the opportunity at Panathinaikos."
Ten Hag also praised Joshua Zirkzee for his debut goal against Fulham, with the Dutchman now in line to make his first start for the 20-time English champions against Brighton.
"Very pleasing that a player who is a striker scores his first goal in is first game, that will give him confidence, very pleased that it's happened," he added.
"The comparison with last year and Rasmus Hojlund and when he scored against Brighton and the VAR looked and five minutes later came to the conclusion the ball crossed the line in the assist and he had to wait thee months for first Premier League goal. It gives him confidence and gives us confidence as a team."
Man United will open September with a home fixture against Liverpool before heading to St Mary's to tackle Southampton in their first game after the September international break.