My 2 cents is you should keep a positive attitude about it and keep in touch with your employer to let them know you're doing everything you can to return to work. No reason to be worked up about something that is out of your control right now.
When you return to your work, the only way your hours can be reduced is for a legitimate business reason, for example, if schedules change by the season, and your hours upon returning are reduced from 8 to 6 because its fall, not summer anymore.
You cannot be fired or unfairly disciplined because you were on workers compensation. Most employers frown on people being out on workers compensation too long, but the money you earn doesn't come directly out of their pocket. Most employers pay insurance carriers for workers comp., so there needs to be a high rate of workers comp going on at your employer for your injury to really affect them. Also, most employers know that the cost of a wrongful termination in California would outweigh the benefit of seeing you on your way out, so maybe your direct manager is upset, but your legal department and HR are going to let it slide.
If your hours are reduced I would recommend you consult directly with your employer to see if there is a legitimate business reason. If there is not a legitimate business reason for your reduced hours or you are terminated without cause, seek a lawyers assistance. But if you don't need a lawyer don't get one at this time. Workers comp is 100% wages in your pocket. Attorneys usually take between 25-33% of the total pie, and also would likely advise you to sit out as long as possible, and sometimes urge a buyout settlement that would net you some nice short term change but put you out of a job. Sometimes that can be an unsaid potential red flag for future employers.