Assistant boss Gary Locke has been named as the interim manager of Kilmarnock following the departure of Allan Johnston.
The former Scotland winger took over at Rugby Park in the summer of 2013 after a successful spell at Queen of the South but yesterday indicated his intention to step down at the end of the season.
However, he has now parted company with the Ayrshire club, who are eighth in the table going into Saturday's rearranged game against Hamilton Accies at New Douglas Park.
A statement on the Kilmarnock website read: "The Board of Directors would like to express its thanks to Allan Johnston for his diligent service over the last 18 months.
"Allan kept the club in the Premiership last season by recording crucial end-of-season victories and an excellent start to the current league season raised expectations.
"Unfortunately, a number of injuries to key players and a series of poor results followed and, although the club sits in eighth place in the Premiership, Allan decided to announce his decision to leave the club to the media on Thursday.
"Allan will stand down as manager with immediate effect and the Board has therefore appointed assistant manager Gary Locke as interim manager pending a permanent appointment. Alan Robertson will provide support as Gary's assistant.
"Applications for the post of manager are invited and will be considered by the Board over the coming weeks."