Dundee have announced that captain Gary Harkins has joined Kilmarnock for an undisclosed fee.
The 26-year-old midfielder helped the club avoid relegation from the first division last season after receiving a 25-point deduction for going into administration.
Dundee chief executive Harry MacLean explained that the club's administrator wanted to release Harkins in October.
But they reached an agreement for the former Partick Thistle man to stay, which the Dens Park club have now honoured by allowing him to join top-flight Killie.
"Unfortunately Gary has decided to join Kilmarnock as a result of an agreement entered into when the club went into administration that he could join an SPL club this summer," MacLean told the club's official website.
"We had hoped that Gary would stay and had prepared budgets accordingly.
"While disappointed that we haven't, as hoped, managed to persuade him to stay, we fully understand his desire to play at as high a level as possible.
"When Gary indicated he'd like to join Kilmarnock we decided to honour our agreement, provided we could reach some sort of agreement (over a fee)."
After signing from Partick in July 2009, Harkins made 70 league appearances for Dundee, scoring 20 goals.
The former Blackburn trainee is Kenny Shiels' second signing this summer having already landed Sheffield Wednesday striker Paul Heffernan.
Shiels became caretaker boss in April after Mixu Paatelainen took the Finland job and he has been named his permanent successor after helping Killie to a fifth-placed finish.