The former Nottingham Forest star, now 20, joined German club Red Bull Leipzig for £13m last August on a five-year contract.
He was a bit-part player in the team which finished second in the Bundesliga and has now been told he can leave.Palace are looking to strengthen their squad after the crushing opening day defeat to Huddersfield – and with Wilf Zaha out injured.
And asked about Burke, De Boer said: “He's a very young promising Scottish player. He had a great season at Leipzig thought he didn't play all the matches. I don't know. He's from GB so always interesting to see those kind of players. Maybe. But we are focusing also on other players."