* Japanese driver back on F1 grid
* Kobayashin missed Belgium, could be dropped again (Recasts with Kobayashi quotes)
By Alan Baldwin
MONZA, Italy, Sept 4 (Reuters) - Japanese driver Kamui Kobayashi was in Tokyo when he received a call on Wednesday telling him he would be racing for Caterham in Sunday's Italian Grand Prix.
Fighting off the fatigue after hurriedly packing his bags and getting on a plane, Kobayashi told reporters on Thursday he was glad to be back in Formula One but uncertain about what the future might hold.
He has not raced since the end of July after being dropped for last month's Belgian Grand Prix - supposedly because the team wanted to get comparative feedback from Germany's triple Le Mans winner Andre Lotterer.
Lotterer, who was making his F1 debut at the age of 32, completed barely two laps at Spa.
"It's not an easy situation. I am here for the sport of racing, but looking at the last couple of weeks I think it's more political stuff happening than sport," Kobayashi told reporters.
"We've had talks with lawyers and this is what we have right now. The team is in a difficult situation. I understand this and I want to help the team."
Caterham changed ownership in July, with Malaysian aviation entrepreneur Tony Fernandes selling to a group of mystery Swiss and Middle Eastern investors whose public face is former F1 team boss Colin Kolles.
Kobayashi, hugely popular at home, had raised money from supporters to secure the drive but Caterham are fighting for survival and in need of more backing.
Spaniard Roberto Merhi, the 23-year-old who could race for the team later in the season once he has secured a superlicence, will make his F1 debut in Friday first practice using Kobayashi's car.
The Japanese said he had been ready to race in Spa and had travelled to Belgium but not gone to the track after being told he was not required.
"They didn't tell me a reason, just that I wasn't driving," he said.
The team's other driver, Swedish rookie Marcus Ericsson, looks secure due to the sponsorship he brings but Kobayashi could be out again for the next race in Singapore if Merhi gets the mileage and stays out of trouble in Monza practice.
Merhi told reporters separately that he did not know whether he would race there.
"At the moment the plan is to do FP1 (first practice) to see how it goes and see how much I can learn about the car and F1," he said.
"Then we will see what is going on and what the next target is. But Singapore is quite a tough place to do a first race, so many corners and in the night." (Editing by Ed Osmond)