BERLIN, Germany - F1 team Sauber is looking at signing seven-times World champion Michael Schumacher, 43, when he leaves Mercedes at the end of 2012.Chief executive officer Monisha Kaltenborn told Bild newspaper: "Of course they are appealing thoughts and of course you consider bringing a seven-times champion on board if he becomes available."FREE SEATSchumacher's manager Sabine Kehm said at the weekend: "Everything is possible."Sauber will have a free seat at the end of the season because driver Sergio Perez is to move to McLaren to take over from Lewis Hamilton who is moving to Mercedes.If he were to join Sauber Schumacher would earn way less and have a less competitive car. Kaltenborn admitted: "We can't compete with Schumacher's previous teams Ferrari and Mercedes."Swiss media, however, said that Force India driver Nico Huelkenberg was considered favourite to take over from Perez.