It is rumoured Caterham is contemplating ousting Jarno Trulli, should Renault refugee Petrov's sponsors agree to buy out the Italian veteran's contract.
The former Lotus squad on Monday announced its test schedule for Jerez this week, with Heikki Kovalainen driving on the first two days, followed by new Dutch test driver Giedo van der Garde.
Trulli is scheduled to drive only on Friday.
Oksana Kosachenko, Petrov's manager, told Ria Novosti news agency that time is running out for a race seat.
"Of course, he is not very comfortable because we expected them to move a little bit faster," she said, referring to an indecisive sponsor.
"Without these decisions, we cannot move forward."
Kosachenko also hinted there are "other options" for Petrov, most likely an official reserve driver role.
"If, within the next few days, we don't succeed, we are going to talk to some other series and probably we are going to talk to Pirelli as well," she added.
