Vote: What caused Italy's failure to qualify for the World Cup?

WATCH: Post-match scenes after Italy fail to qualify (0:49)

Watch the reaction of Italy's players after the four-time world champions missed qualifying for a 15th straight World Cup. (0:49)

A 0-0 draw against Sweden in the second leg of a UEFA World Cup qualifier playoff on Monday means that Italy will not participate in the competition for the first time since 1958.

The Azzurri, the four-time champions, have become the latest high-profile team to miss out on Russia 2018. ESPN FC senior football writer Mark Ogden writes that there are multiple reasons for their failure to qualify, from the hiring of Gian Piero Ventura as coach two years ago to the players who had been selected for the team.

After the game, midfielder Daniele De Rossi and defenders Giorgio Chiellini and Andrea Barzagli announced they would be retiring from international competition -- joining goalkeeper Gianluigi Buffon, who previously said he would do so after the World Cup.

What do you think? Weigh in on the reasons why you think Italy did not qualify, as well as which retiring player the Azzurri will miss most, in our poll below.

Twenty-nine teams have already qualified for the 32-team competition, which will begin when hosts Russia open with a group-stage game in Moscow on June 14.