Koeman told Barkley in May that he would be sold if he did not accept the contract on offer. He said on Wednesday that Everton had not received any bids for the player, who is currently recovering after groin surgery.
"His situation is not too difficult, we made a good offer of a contract, he declined and told me that he is looking for a new challenge," Koeman told reporters before Everton's Europa League qualifier first leg against Slovakia's Ruzomberok on Thursday.
"It is really clear. I am looking to other players – that is my priority and not Ross, with all respect, because it is his decision. Everybody knows what the situation is. He told me at the end of last season," he said.
"He has one more year on his contract and we work with respectful people. And after his surgery, if he is back for training, he will be part of the first team sessions. There have been no changes - he has been the same.”
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Everton have signed eight players ahead of the new season, but Koeman wants three more as he aims to replace long-term absentee Ramirez Funes Mori (knee) and striker Romelu Lukaku, who has joined Manchester United.
"We lost Funes Mori to injury, we are looking to replace him," he added. "We lost Lukaku, so we try to get another in and maybe one more."
The manager also confirmed the Everton's pursuit of Swansea City midfielder Gylfi Sigurdsson, but said he did not know if the club would table another bid.
"Of course we have interest in the player," Koeman added.
British media reported that Everton have had bids of 40 million pounds ($52.2 million) and 45 million pounds for the Iceland international rejected by Swansea.
(Reporting by Aditi Prakash in Bengaluru)
