Arsene Wenger is puzzled over the decision to expand the European Championship finals.
Uefa announced last month that 24 teams would go through from the qualifying stages from 2016 - only 16 countries competed at Euro 2008.
"They were talking about it at the European Championships in Austria and Switzerland but it was a complete surprise to me," the Arsenal boss told his club's official website.
"I didn't completely understand the reason behind that. It makes the qualifiers less interesting because you will have over 50 countries (competing) and 24 go through."
Wenger is also struggling to understand how the competition will work as 24 teams are narrowed down to eight or 16 in the knockout rounds.
He said: "I don't know the details. Will there be one round more in the finals and they will play a last 16 (round) to qualify?
"This means you will have 16 teams qualifying out of that 24 and that will make the groups less interesting than this time.
"It looks like everybody, individually, understands the need to reduce the number of games but historically you always get more.
"It may be keeping everybody happy but I don't think it will raise the level of the competition."