The Sweden international is guaranteed to remain at the Hawthorns until at least January with the closure of the transfer window but Clarke hopes he will remain on a long-term basis.
"It was very important Jonas stayed. Anyone who has followed West Brom over the years, knows Jonas is an integral part of team. He's crucial," he said.
"I think keeping him is a statement from the club in that they have key players - but they don't have to cash in on them.
"It might be a risk but maybe if we keep winning matches it will make his decision easier to sign a new contract."