Franz Tost has named three drivers he considers "suitable" for Toro Rosso to target.
The Austrian admitted that his premier choices - Vettel, Hamilton, Alonso and Rosberg - are "unlikely" to want to drive for Red Bull's secondary team.
"So when thinking of suitable guys I would pick three, if I may," the Toro Rosso team principal told F1's official website.
Tost mentioned Paul di Resta and Nico Hulkenberg, and also Romain Grosjean, the former Renault driver who is on the cusp of winning the GP2 title and reportedly in talks with up to three teams for the 2012 season.
"Renault burned Grosjean when they teamed him up with Alonso (in 2009), but I still believe he's got huge potential," he said.
Tost acknowledged however that it is Toro Rosso's owner that selects the drivers for his team.
"Well, Red Bull are choosing the drivers from their pool. But that was always the intention and the reason for this team to exist," he said.