Barcelona will reportedly be forced to wait after Euro 2020 to complete a move for Georginio Wijnaldum.
Barca staff had reportedly been hopeful of being allowed to conduct Wijnaldum's medical from the Netherlands' training base, where the national team are preparing for Euro 2020.
"Those players will have to be patient until after the tournament [to undergo their medicals]," De Boer told reporters when questioned on the issue.
According to Italian journalist Fabrizio Romano, who posted an update on his Twitter account, Wijnaldum has agreed a contract at Camp Nou until June 2024.
The Dutchman leaves Liverpool having scored 22 times and registered 16 assists in 237 appearances for the Merseyside giants, winning the Premier League, Champions League, UEFA Super Cup and Club World Cup in the process.