Jolyon Palmer says he is going "flat out" to secure a 2016 race seat, but concedes if he doesn't get one then he is unlikely to stay in F1.
The 24-year-old was appointed Lotus reserve at the start of the 2015 campaign and he has already had nine Free Practice 1 outings in place of Romain Grosjean this year.
However, he has made it clear that he wants to make the step up to the grid next year and his "aim is still to be racing with Lotus", who will be taken over by Renault next year.
The Enstone squad have already confirmed Pastor Maldonado for 2016, but they do have a vacant seat as Romain Grosjean has joined the new American-based Haas F1 Team.
"I would say it is probably racing or nothing," Palmer told Autosport. "I'm enjoying what I'm doing. Having not been in F1 before, to drive the car as often as I have has been great, and to be involved in a team you learn a lot.
"But having done one year of it, I feel I wouldn't be learning a huge amount by doing another year doing the same thing with the same team.
"I'm flat out for racing next year. There's a chance. It just depends on the outcome of a lot of things."
Renault are yet to reveal their plans for 2016 once their takeover of Lotus is complete, but Palmer feels he has done enough to prove to everyone at Enstone that he is worthy of a seat.
"The people here [at Lotus] know the job I've done and the job I can do," he said. "I expect the team will stay largely the same, although maybe the management will change, but all I can do is show the people here what I can do.
"I'm definitely ready to be racing in F1. I'll be in the car quite a few more times this season, an unconfirmed amount, which is a positive.
"Every time I'm back in it's a chance to show what I can do, and while everything is undecided, it's a good chance to prove why I should be in."