After Schumacher complained about Ferrari's lack of competitiveness last year in a separate interview with Der Spiegel magazine, Willi Weber reminded Bild of Toyota's 'Nothing is impossible' advertising slogan.
"There have always been surprises in Formula One," Weber said, when asked about Schumacher's comment that there was a one percent chance he would move to a new team after his Ferrari contract expires at the end of 2006.
"And even if McLaren has (Fernando) Alonso in 2007, there are still big players in the market."
Schumacher, 37, has won seven world championships but managed just one victory in 2005 and finished a distant third behind Renault's Alonso and McLaren's Kimi Raikkonen.
Spaniard Alonso has signed to race for McLaren in 2007 while Raikkonen is seen as a likely replacement for Schumacher should the German leave Ferrari.
Schumacher said he would not want to extend his career beyond 2006
"How does that Toyota slogan go again?" Weber said, referring to the adverts in Germany. "Let's wait and see how the season starts. There's enough time before the summer. Before that there won't be any decision."
Toyota are based near Schumacher's home town of Cologne and already have his younger brother Ralf as one of their two drivers.
Weber was Ralf's manager when he steered him from Williams to Toyota for a three-year deal worth 15 million euros per year but the two have since parted.
"That was my greatest triumph," said Weber, who has previously said he would not want both Schumachers driving on the same team as long as he was their manager because one would always be the loser.
"That's no longer my problem," Weber said. "What was true in the past isn't always true today."