"He doesn't want to leave, but maybe he will if he doesn't get a deal," Harrison told BBC Sport.
"I can't see things working themselves out as they stand at the moment."
"Jussi has been at Bolton for eight-and-a-half years and is settled there.
"In my view, he is one of the best three keepers in the Premiership."
Contract talks between the 30-year-old keeper and the club have stalled mainly because of pay demands.
Meanwhile, Bolton's Kevin Davies has moved to defend his poor disciplinary record.
"I never have any intent to hurt anybody but there's a physical part of my game," he told Sky Sports News.
"Some referees like it, some don't. As they see it I'm backing in or being pushed. It's a bit frustrating at times and sometimes you feel that you don't get the decisions but you have to get on with it.
"I've only had five yellow cards this season so that's not too bad, you know. In some games the other teams obviously study the way you're playing and they put an extra man in front of you and a couple behind you.
"So it's been more difficult for me this season to be successful in that stage of play but it's something I enjoy immensely."