The German, a three-time Le Mans winner, has been given a one-race deal to take Kobayashi's seat in Spa.
Lotterer tested for Jaguar in 2001 and 2002, and Caterham revealed that they have turned to the 32-year-old in order to gain feedback in order to improve the performance of the car.
"I'm ready for this challenge and I cannot wait to jump in the car and make the most out of the weekend ahead," Lotterer said.
"I will need to get settled and used to the car quickly, as the team has worked on a number of updates and we will need to have as much time as possible out on track to optimise the car's performance.
"I really enjoy racing at the legendary circuit of Spa-Francorchamps, it's one of my favourite tracks and it's very close to where I grew up, so this makes the weekend even more special and one to remember."
Caterham stated that Kobayashi will remain "part of the team" despite being overlooked for this weekend's race.