The winger has admitted the players were even scared of the home supporters, as they knew that no one was happy with the way they were playing.
"Everything changed after Koeman left. The football played by Big Sam was awful, if it could even be called football," Vlasic told Croatian newspaper Sportske Novosti.
"In such football I do not have a place. The football team was terrified by everything, the fans mostly. This season, Marco Silva plays different, much nicer football, but has not got results.
"It is true that Everton did not make an expected breakthrough but at least fans now look at the normal football in which the guys, through their actions, are trying to score and win."