Speaking in Korea, the Swiss team's boss Monisha Kaltenborn said "let's see" when asked about the speculation.
And Barrichello, 41, wrote on Twitter: "Lots of things have been said this week about a possible F1 return.
"The truth is: if there is an opportunity, I'm in."
His friend and compatriot Felipe Massa, who is also fighting for a seat in 2014, said he would welcome Barrichello back to F1.
"He cannot stay at home," smiled Massa, referring to the fact Barrichello is now a commentator for Brazilian television Globo.
"Hopefully it will be possible for him to return, because it has to do with the financial side at Sauber," he told Totalrace.