Frederic Vasseur is not denying speculation Kimi Raikkonen could switch to Sauber for 2019.
The Swiss team's boss was also asked by a reporter about a rumour linking Sergio Perez to Sauber.
"It's very nice that the team attracts strong drivers," said Vasseur. "This allows us to choose rather than wait for the decision of other teams."
Asked if he has Raikkonen's phone number, he laughed: "I have every driver's number!"
Raikkonen, now 38, started his career with Sauber in 2001.
"We will discuss the issue with Ferrari and then we will make a decision," said the Sauber chief.
"For Alfa Romeo it is important that the team achieve good results, so we need to find two drivers that are suited for our future."
Raikkonen himself said at Hockenheim that he is hoping for certainty as soon as possible.
"Knowing what I am doing is important in many ways, and not just for me. My family also wants clarity," said the Finn.
"So I hope that we will have a decision soon. But as I said, you have to ask the team."
Raikkonen is third in the driver rankings ahead of tomorrow's German Grand Prix.