Oldham Athletic can confirm that first team manager Lee Johnson has left the club to join Barnsley Football Club after compensation was agreed between the two clubs.
Johnson ends a two-year tenure with Latics after taking over the club in March 2013.
Guiding the club to safety in the 2012/13 season, Johnson's first full campaign ended with a 15th-placed finish in Sky Bet League One.
After a summer overhaul of staff and players, Latics now sit two points outside the play-off places ahead of Saturday's clash with Preston North End.
Chief Executive, Neil Joy, said: "Whilst extremely disappointed that Lee has left the club, Oldham Athletic would like to thank him for the commitment and desire he has given to his role over the last two years and the contribution he has made to the development of the football club.
"We took a gamble in appointing the youngest manager in the Football League when he joined us and he has proved what we believed to be true at the time in that he is developing into one of the best young coaches in the country.
"He has always had the full support of the Board of Directors at the club especially when it has come to improving the quality and strength in depth of the playing squad.
"We wish Lee every success in his new role at Barnsley."
Latics can also confirm that Tommy Wright has left to join Johnson at Barnsley.