The 26-year-old switched from Moto2 to SBK at the start of the 2015 season and finished regularly in the top 10 during the first four rounds.
However, he fractured his right wrist during a crash at the Assen event in the middle of May and was forced to watch the race at Imola from the sidelines.
He was back on the Ducati Panigale R at Donington Park as well as Portimao last time out, but the Portugal round has turned out to be his last appearance for a while as he has decided to take a break following his split from Althea Racing.
"I embarked on this challenge with great enthusiasm," he said. "I immediately had good feeling with the team and with the bike, right from the first tests, which made me think that I was regaining the right sensations with which to start going fast. But things got more complicated after some crashes and after an injury which put me a step back.
"I believe that, for the good of both parties, the best solution is for me to take a break. The team is working hard and I cannot repay their trust in this way, even if on my side I really wanted to be able to do well. I can only thank Genesio Bevilacqua and the entire team for these months spent together. Now I need to stop and reflect and find a way to get back to feeling like a strong rider and turn the page after the last very difficult 18 months."
Team manager Bevilacqua had nothing but praise for Terol even though things did not turn work out between the two parties.
"I want to thank Nico for this, albeit brief, relationship that we have had because, as well as being a rider, he has proved to be an extraordinary guy on a human level," he said. "We have tried together to find the path that would help him return to a high level and the team never gave up in trying to meet the rider's needs. It is sad but true to say that we have not met each others' needs.
"I want to wish Nico all the best for the future and hope that this period of uncertainty in his career will soon be behind him, so that he can return to being the great champion that he was and be happy riding a bike. Personally, but also on behalf of the whole Althea team, I wish him all the best."