That information should be in the papers you received. If you read your long term disability papers from your employer, I think you will find the answer. It falls under the employers HR policy.
1 yr is the normal time table I believe, if you haven't been able to work that whole time ,they do not have to keep your job open indefinitely.
Now if they fired or terminated you for filing a wc claim - that would be different. but since you mention it's been a year of no work for you, that is probably the reason.
some info-
http://www.google.com/search?hl=en&s...&aq=f&oq=&aqi=