The economic literature on this type of mandate is clear. Although government can offer people something for nothing, the labor market does not. Employee benefits are not gifts from employers. They are substitutes for money wages and other benefits. The cost of the employer mandate will surely be borne by the employees themselves.
We can be fairly certain that low-wage workers and their employers will be searching for ways to avoid the mandate. Why? If the employees were willing to spend half their income on health insurance they would have done so already. That they have not indicates they would rather spend the money on something else.