A spokeswoman representing Burns said: "I can confirm that we have left Warren's and Ricky is considering his options."
Last week, English super-middleweight prospect George Groves agreed terms to defect to Matchroom Boxing, a move which was confirmed on Monday.
That and the postponement of Burns’ unification bout with IBF title-holder Miguel Vazquez led to Warren’s big ‘Rule Britannia’ card on March 16 being moved to April 20.
But now it appears that Burns – who has seen a stream of opponents drop out of signed bouts to meet the Scot since he stopped Kevin Mitchell in September – has reached the end of his tether following the Mexican’s withdrawal due to food poisoning.
Burns's manager Alex Morrison told The Scotsman: “I regret it has come to this because I have known Frank for nearly 40 years, but it has to be done for Ricky's sake.
“I felt we had to do something to stop Ricky stagnating. Two fights have been called off after he has trained hard for them and it was not even certain that the bout with Vazquez would have gone ahead on April 20.
“In fact, I now doubt very much that fight was ever going to happen. Vazquez was supposed to be sick but five days later I'm told he was seen sparring in the States.
“There were also a lot of issues I wanted settled before Ricky fought again and these were not concluded satisfactorily. I'm quite sorry this has happened, but I have to safeguard Ricky's future and he feels himself that he now wants to move in another direction.”
Burns saw December bouts with first Liam Walsh and then Jose Ocampo scuppered when each man pulled out, with the December 15 card at London’s ExCeL instead headlined by Groves’ win over Glen Johnson, which would ironically be his last as a Warren competitor.
The unification fight with Vazquez is now at risk of not happening at all, with Morrison reportedly adamant his charge's next fight will again be in Glasgow.
Rumours persist that Burns’ next move will be to follow Groves to Matchroom, though with Golden Boy also housing WBC lightweight champ Adrien Broner and moving forward with British expansion plans, they can not be ruled out.
