The 28 year old has joined the Latics outside the transfer window as a free agent after leaving New York Red Bulls at the end of his contract in December.
Speaking about the addition to the Wigan Evening Post, Rosler said: "It's a great opportunity to bring in a very experienced player, who has captained the New York Red Bulls.
"I also know him from his time in Sweden with Helsingborgs, when he played in a championship-winning side.
"Markus is 28, at the best age of his career, and he offers us the kind of qualities we are looking for.
"He is a ball-playing centre-half, a very smart player, who understands he has to adapt very quickly to the physicality of the English game.
"I just feel that, because of the problems we've faced since I've been here in defence, it was necessary.
"We've had to play the same two centre-backs more or less every single week, sometimes with no cover, and we needed to strengthen.
"The MLS season finished a while ago, but he has been training back in Sweden with Helsingborgs for the last few weeks and he has impressed us with his fitness levels.
"You could see straight away that he was in a good condition.
"Is he in top condition? I don't think so, because you need to play games for that, but I feel he is in good enough shape to compete for a place."
Holgersson is expected to go straight into contention for a first team spot and relieve some of the pressure on Leon Barnett and Emmerson Boyce.