"Let's ignore outsiders' voices." the Dutch international told the club's official website.
"We know what needs improving; we just need to keep analyzing and fixing our own performances. We've not yet failed to recover from bad times.
The Rossoneri struggle in the league and dropped to the 11th place with only seven points from six games.
But Seedorf still believes the European Champions can resotre thier from if they stayed together and worked hard.
"Now's not the time for talking. We'll go out onto the pitch and do it as a cohesive unit," he said.
"We're Europe's champions, so teams raise their game against us. The results don't reveal everything."
Milan will travel to Glascow to meet Celtic. The Milanese won their group stage opener 2-1 against Benfica.