Can my California employer require me to use accrued sick leave rather than work remotely while I am recuperating?
I am not a lawyer, nor do I play one on television.
But, barring something to the contrary contained in your contract, it is my understanding that your California employer can require indeed you to work in the office, rather than remotely. Yahoo (headquartered in Sunnyvale, CA) reversed their remote work policy not too long ago.
And if you cannot come into the office for some reason, and aren't permitted to work remotely, it's my understanding that your employer can indeed force you to take a day off - using up accrued vacation time, personal time, or sick time as dictated by the rules in your company.
If I am able to work, just not able to commute into the office, and am only not working on my employer's order, should that come out of my sick time?
Should is a personal opinion.
Some companies have blanket PTO days, where accrued days off cover vacation, personal time, and sick time. If your company has such a policy, and doesn't permit working remotely, I feel that is where your "unable to work" days should come from.
I am happy that my company fosters flexible work arrangements, and ad-hoc remote work. I personally believe that for trusted knowledge/office workers, this is a proper policy - one that works out well for both the company and for the workers. I'm sad to hear that your company's policies have changed.