I took leave from my job for knee surgery. When I was ready to return to my job as a warehouse foreman, my company asked me to take a fitness-for-duty exam. After the exam, my doctor sent my employer a detailed write-up of my condition and status -- including that I have rheumatoid arthritis. My company put off returning me to work for a couple of weeks, then told me not to come back. My written termination letter and severance package state that I was laid off, but my manager told me that the company didn't want me back because they were worried my physical condition would continue to worsen and I would need more surgery (with the time off and health insurance costs that requires). They hired someone else to replace me. Is this legal?