Antonsson, who is currently leading scorer in Sweden’s top flight, will have a medical with an English club today, Kalmar confirmed over the weekend.
Kalmar president Mattias Rosenlund refused to name the club, who have bid in the region of £1m for Antonsson, and insisted the deal was not complete, but he said an agreement was in place for the 25-year-old Swede to move to England from his homeland.
Antonsson attracted attention with a flurry of 10 goals in 12 games in Sweden’s Allsvenskan division this season.
He joined Kalmar from Swedish lower league side Halmstads BK last year and has averaged close to a goal from every two matches during his time in the top flight.
In his spell at Halmstads, Antonsson played for a while under Pep Clotet, the Spaniard who was named last week as assistant to new Leeds head coach Garry Monk.
His arrival at Elland Road would be the first stage of United’s attempt to strengthen the attacking end of a squad who struggled in the Championship last term, producing 50 goals in 46 games.
Leeds and Aston Villa have both been linked with Antonsson in the past month.
Kalmar president Roselund said: “We are in agreement with a club. He will undergo a medical on Monday to check that nothing interferes with the process. That is what we are waiting for.
“We are satisfied with the agreement, that much I can say about it. It will be good for all parties. We’ve agreed and Antonsson has agreed with the club. Formally it is not completed yet.”