The former Celtic star is set for his first Champions League appearance for Alex Ferguson’s team against Lille in nearby Lens later Tuesday.
But the 35-year-old has said he will return to Swedish parent club Helsingborgs on March 12 as originally planned, a week after the second leg against the French club.
“I am not saying that I am not flattered or grateful to get the opportunity to extend my stay but there are other things I need to think about,” he said.
“The Swedish season starts at the end of March and I need to get back to that. I will stay only until March 12.”
Larsson said that although he had been enjoying his time at Manchester, the travel to and from Sweden had been testing.
“I am going back and forward and it’s not an ideal situation,” he said.
“This is a great adventure for me. I arrived in January and I’m going home in March to play in Sweden. It suits me perfectly.”