I have been injured on the job in California and had to have knee surgery. I am recovering right on schedule. My employer has asked me to talk to a workers comp claim adjuster because my employer says that the builder where I got hurt may have been negligent, and my employer wants to do a cross complaint. Is required that I talk to the adjuster? I do plan to return to the company when I have recovered.

Yes, you need to talk to the adjuster. It sounds like your employer's WC carrier is trying to determine whether they can subrogate the claim with the builder's insurance carrier. This will have no impact on the handling of your WC claim whatsoever and will only help your employer if you cooperate. If they can "charge back" your WC claim to another insurance carrier, that means your employer's WC premiums won't be impacted by your claim - and that's good news for the company and the employees. Worker's compensation insurance is not cheap.