"制陶坯的工人" can be translated into English as "clay坯（这里坯实际指未烧制的陶器形状，专业术语可用 'greenware' 或更通俗的 'unfired clay ware' 表达，但直接描述工人时侧重动作）former" or more naturally and commonly as "pottery clay former" or "worker who shapes clay for pottery".
In a more concise and idiomatic way, you could say:
"Clay former (for pottery)"
"Pottery clay shaper"
"Worker who molds clay for pottery"
The most straightforward and commonly used expression among these might be "clay former (in pottery making)" or simply "pottery clay worker" if the context makes it clear that the worker is involved in shaping the clay for pottery.
For simplicity and clarity, "clay former" (with the understanding that it refers to forming clay for pottery) or "pottery clay shaper" would work well in most contexts. If you want to be very precise, you could say "a worker who specializes in shaping clay into pottery blanks" (where "blanks" refers to the unfinished, unfired pottery shapes). However, for brevity, "clay former" or "pottery clay worker" are adequate.