Jol fears goalkeeper Stekelenburg needs a shoulder operation and could be out for months.
Jol said: "If it is not right in two weeks' time, then he will probably need an operation.
"It's already five weeks now, so it's certainly long term. He had a few injections in his shoulder and it's quite sensitive.
''He trains but when he stretches he feels a lot of pain, so we have to be very careful."