Bruno Senna has revealed that he has only been confirmed as a Renault driver for the next two races due to legal matters.
Renault announced late on Wednesday that the 27-year-old would replace Nick Heidfeld at the Belgian Grand Prix but didn't divulge any further details.
However, Senna told the FIA press conference at Spa on Thursday that the Brazilian has been provisionally pencilled in for just the Belgian and Italian Grands Prix due to legal proceedings.
"Right now I am confirmed to do this race and the next race, but there are some legal issues to be resolved," Senna said. "I cannot confirm if I am doing rest of the year or not. The intention is I am going to do it, but it still cannot be confirmed."
Senna, who was given the Friday driving duties in place of Heidfeld at the Hungarian Grand Prix, concedes he faces a difficult task, but is keen to repay the team.
"It is going to be a big challenge to come back into the middle of the season, a bit later than the middle of the season, to go racing," he said.
"But I have been participating in all the meetings with the engineers, and am up-to-date with all that is going on at team. Hungary was useful to know how the car could go, but it will be an uphill battle to get on the form of these guys here [other drivers in the press conference] who have been racing for 11 races now. But I am really looking forward to it, hoping to progress fast and repay the faith the team has given me.
"Friday was very tough in Hungary, it was really difficult. I know I have to learn how to deal with the tyres from the first set to qualifying, and learn how to deal with tyres in the race. All this experience I don't have, so it will be the first time. If I can be anywhere near Petrov, that will be a good reference."
Team principal Eric Boullier feels Senna has the right qualities to drive for Renault.
"We are happy to provide Bruno with the chance to begin racing with Lotus Renault GP, starting at Spa-Francorchamps this weekend," the Frenchman said. "He has proved himself to be an attentive member of the team since he joined almost seven months ago, and we are confident that he will demonstrate his ability alongside Vitaly (Petrov)."
Renault said on their team website that their "present intention is to give Bruno the opportunity to race for the rest of the season. However, some legal issues have not been fully resolved as yet and, as a result, the team will make another announcement on this matter in due course."
Speculation was rife earlier this week at Heidfeld was unhappy with the team's plans to replace him with Senna and threatened to take legal action if they went with the move.
The Telegraph's F1 correspondent Tom Cary revealed via Twitter on Thursday that 'Heidfeld went to court yesterday to try to hang on to his Renault seat'.
Heidfeld: I have a valid contract