Clarke expects Olsson to stay and is also hopeful his clause will not be activated by any of the clubs listed in his contract.
Asked whether it would be an issue this summer, Clarke replied: "Like I said in January, no I don't.
"The speculation is based on the story from January. I spoke about it then and I don't want to speak about it again. He's a key player for the club and he's been a key player for a number of years."