"Mattias has had a full pre-season and he's also had two games for Brondby in Denmark so he's up to speed, he's ready to go," said the City boss, who received international clearance for the player from the Danish FA yesterday.
"There wouldn't be a problem putting him straight into the side."
Worthington also confirmed that he had to battle with several other clubs in order to capture Jonson's signature.
"There were a number of people chasing his signature and there was one club who were particularly keen," he said. "Just prior to him going in for his medical his mobile phone went off and they were saying 'Don't join Norwich, come and sign for us'.
"But he'd been here, talked to us and seen what we had to offer and decided we were the right club for him. He feels he has made the right decision."
Jonson has also been given international clearance by the English and Danish FA's. He is now set to make his debut against Crystal Palace at Carrow Road on Saturday.
OTBC