Former South African white-ball captain Johan Botha on Tuesday quit as coach of Queensland and the Big Bash League side Brisbane Heat with a year left on his contract.
The 44-year-old steered Queensland to the Sheffield Shield final in his first year at the helm, but failed to win a trophy, with reports saying he was forced out.
Former Australia test captain Tim Paine, currently head coach of Australia A, is among those being touted as a replacement.
Queensland Cricket chief Terry Svenson thanked Botha for his commitment.
"While we haven't achieved all of our on-field goals, Johan has made a strong contribution towards the development of the next generation of Queensland and Brisbane Heat players," he said.
"Despite this decision, Johan's contributions to our high-performance group have been valued."
Botha played five tests, 78 ODIs and 40 T20 internationals for South Africa between 2005 and 2012, captaining both white-ball sides during that time.
He was previously head coach of the Multan Sultans, Karachi Kings and Islamabad United in the Pakistan Super League.