It entirely depends on the circumstances;
if you're talking about can you be made redundant because, for example, several people are being made redundant at the same time, then yes - you don't have to be in the work place for this to effect you.
if you are talking about being made redundant because of your absence, then it depends;
if it's a one off occasion and you've been signed off for a short period then it would probably be considered a bit too soon.
if you've been off for longer and show no sign of coming back and the business can justify the reason for needing the role filled, they could argue the business need.