The Elland Road favourite joined the Bees on a three-year deal following his fallout with manager Marcelo Bielsa.
The 28-year-old joined Leeds from Torino in 2016, and went on to make 120 appearances, including 44 last season.
Jansson had established himself as a key player for the Whites since arriving, making the Championship Team of the Year last season as the side finished third and lost to Derby County in the semifinals of the play-offs.
His disciplinary shortcomings with former bosses Gary Monk and Paul Heckingbottom, coupled with Bielsa’s willingness to let him go, meant the club had no choice this summer, and captain Liam Cooper has reacted to the Swede’s departure.
“It’s always a surprise, but at the end of the day, the club has got to do what they got to do,” he told the Press Association in Australia.
“He was a great player, he was well-loved, we just wish him all the best in his new adventure.”
— Simon Peach (@SimonPeach) July 15, 2019
Despite his issues, Jansson was very popular with the players and fans, and they would have wished things were sorted out between him and the manager.
His exit is a huge blow on the defensive department, though, but Bielsa will ensure that he gets things sorted out so that his input wouldn’t be missed.