While it possibly is the job we are after, I'd nevertheless say "No".
Even though it is the only "Creature Design" credit (and only appearing in a few episodes, if I recall correctly), it is (IMO) too vague. But this is mostly because I don't know if a "Sketch Artist" does the actual design, or if he is simply pinning down the ideas of someone else.

Raises the question, who really designs the creatures? The person who draws what they will eventually look like from nothing, or the sculptors who take the sketches and make them live in 3D? I'd keep the credit local myself as I do believe it fits creature design (and the sketches are the true design IMO), just not sure it fits the wording of contribution rules.

According to each of their websites, they are creature designers.  I would enter them.

Quoting Lewis_Prothero:

Quote:
question is what did the "Sketch Artist" actually do to deserve a credit?

The original sketch would be the first step of original design, at least that makes sense to me.
Although it could raise more questions. For instance, Evil Dead 2 and "the pit witch". I can't recall who did design that, someone from KNB, but remember hearing them say Sam Raimi asked for "a heinous horror hag". Then someone drew it and others made it. Does Sam get a credit for that idea? The artist brought it to life on paper, and the effects wizards brought that to 3D.