The 27-year-old Montenegro international made 111 appearances for Preston, scoring 31 goals, but his spell at the Championship club was marked by several disciplinary issues.
Osmajic received an eight-match suspension in October 2024 after being found guilty of biting Blackburn Rovers defender Owen Beck.
He was later charged with racially abusing Burnley midfielder Hannibal Mejbri and received a nine-game ban last November.
The forward was subsequently sent off for violent conduct against Hull City in his fourth Championship appearance after returning from suspension.
Osmajic featured in Preston’s opening-day defeat by Bolton Wanderers but was absent from the squad for Saturday’s loss to Wolverhampton Wanderers.
