They cant pressure you but they can make you feel guilty
And it all depends what�s wrong with you as well
Take my husband he had a break down was off work for 6 weeks
Then they started asking to see if they could help and wanted to see him etc
So he went back part time etc .
Just check your contract for how long you can be on sick leave on pay
They can ask that you attend a company doctor's appointment at their expense for a second opinion. That might lead to a discussion where you are asked to consider doing some part of your job - within the capabilities of your illness/absence.
Some people see it as within their responsibility to work with their employer to try and find ways to minimise the loss of an expensive resource.
Then there are others that see their role as to try and stay 'on the sick' as long as possible.
Alternatively, it may only be pressure in the sense that if they let it run on too long there's a reasonable chance they will start thinking along the lines of dismissing the person on the grounds that he/she has an unsatisfactory attendance record (which can include sick leave). So maybe its just encouragement to try and get the person back to work asap?
With my job, they will expect you to do other duties or work elsewhere if you cannot do your usual job.
Last year I had a bad knee and 3 months off. They wanted me to work elsewhere internally, but I (succesfully) argued that having to travel to this other place would cause problems with the recovery of the knee. Too far and long by public transport, too painful and dangerous if I tried to drive.
First and foremost I would expect your company have been informed with you sending them a Doctor's sick certificate.
Second before the Company make any demands and it depends on your illness a letter to see a company's doctor. As assessment will be made and it depends on the Co Doctor receiving you family Doctor's certificate he/she will assess you.
If you go back to work without a demand made by the Co you take any risk of liability. If the Co have demanded you return by letter with threats they are liable for any injury to your health and safety. Here I have to mention on a company with integrity.
But if you are working with a very small company of a few persons then they may not have any integrity but only a Swaztika as a company logo
Yes, your employer can expect you to come back. A good employer would get some medical opinion to see what temporary accommodation they could make to help you return to work albeit it on a phase back.