Sources have told ESPN that Koeman is in advanced talks to take over the role of Barcelona head coach after Quique Setien was sacked on Monday.
Koeman has a clause in his contract with the national organisation that would allow him to leave if Barcelona offered him a job as boss.
"I can't say much before everything is signed. It is about the details now but it could very well be it will be final today," Koeman told Fox Sports.
"I didn't expect things to go this fast, and it is not the best timing. It took me by surprise as well but Barcelona is the only club for which I had a release clause in my contract. It's ugly for the Dutch FA but not unexpected."
Koeman, who was part of Johan Cruyff's "Dream Team" as a player at Barca and later acted as Louis van Gaal's assistant at Camp Nou, has always said that managing the Catalan club would be his dream job.
He played with with the club from 1989 to 1995 and won four La Liga titles as well as the 1992 European Cup, where he scored the winning goal.
He was named Netherlands boss in February 2018 after they failed to qualify for the World Cup and his contract was supposed to keep him with the national side until Qatar 2022.
This isn't the first time Koeman's name has been linked with the job as he was also suggested as a possible replacement for Ernesto Valverde.