He is expected to leave the Northern Ireland job after five and a half years, during which time he has led the country to its first ever European Championship finals and the brink of a first World Cup in 32 years before Sunday's play-off defeat by Switzerland.
The Swiss qualified 1-0 on aggregate, the tie ultimately being decided by the hugely controversial penalty converted by Ricardo Rodriguez in the first leg in Belfast on Thursday.
Croatia, who had beaten Greece 4-1 in last week's first leg in Zagreb, will be playing in their fifth World Cup.
"But we know on the other side that management is such a hard job".
For the first 30 minutes Greece were in control.
Greece continued to enjoy more of the ball in the second period but when it came to finishing off an attack, either a pass would go astray or a defender would step in.
Iranian Presence in Syria Is Legitimate, Russia Says Amid Israeli Concerns
Israeli Prime Minister Benjamin Netanyahu (2nd L) attends the weekly cabinet meeting at his office in Jerusalem November 12, 2017. Israel has largely stayed out of the war but has struck suspected weapon convoys to Hezbollah.
Northern Ireland manager Michael O'Neills' odds to become next Rangers manager have shortened after his side failed to qualify for next summer's World Cup - but Gers fans don't want him anywhere near Ibrox.
Greece did put the ball in the net in the 79th minute, but substitute Dimitris Pelkas was correctly called offside.Bologna defender Vasilis Torosidis' shot was blocked by Subasic with just three minutes left, denying Greece even a consolation strike. "The players are devastated but I couldn't be any prouder".
Despite his heroics in charge of his national side, O'Neill's lack of experience at club level is scaring Rangers fans off.
Switzerland scraped into their fourth finals in a row 1-0 on aggregate, after being held at home by a valiant and workmanlike Northern Ireland who came desperately close to forcing extra-time.
"But from a football point of view, Michael's first thought is to defend and he has Premier League defenders in the Northern Ireland squad".