The League of Nations and how it impacts Euro2020:
League A:12 teams; 4 groups of 3
League B: 12 teams; 4 groups of 3
League C: 15 teams; 1 groups of 3 and 3 groups of 4
League D: 16 teams; 4 groups of 4
(55 teams)
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Teams that top their group in League A go into a semi final and final to determine the UEFA Nations League winner in Jun-2019.
Teams that top their group in Leagues B, C and D get promoted to Leagues A, B and C respectively for 2020.
Teams that bottom their group in Leagues A, B and C get relegated to Leagues B, C and D respectively for 2020.
One League A group has Spain, England and Croatia; and so one of these nations will be relegated into League B for 2020
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UEFA Euro2020 Qualifiers: 5 Groups of 5 and 5 Groups of 6 (55 teams) (Groups A-J)
Top 2 in each Group automatically qualify for Euro2020 i.e. 20 teams automatically qualify.
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Remaining 4 position in Euro2020 will come from League of Nations.
How?
In each of the Leagues A-D, the top 4 ranked teams that did not qualify for EURO2020 will enter a play-off in Mar-2020 with one finals place on offer per League i.e. a semi-final and final per League. E.g. if Greece tops it's group in League C and doesn't automatically qualify for Euro2020 then it will be guaranteed a semi-final play-off match in Mar-2020 with other top ranked teams in League C that also did not qualify.
This means that 1 team from League D will make it to the Euro2020 finals.
What about if all the nations in League A automatically qualify for Euro2020?
Then, the top 4 ranked teams in League B that did not automatically qualify for Euro2020 takes the place of League A and then the next 4 ranked teams in League B enter a play-off for Euro2020.
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What does this mean for Greece's chances?
We need to top our Group in League of Nations! Not only does it give us a 2nd chance to make Euro2020 in the event we don't automatically qualify, but it also means we get promoted into League B in 2020.