YES

(VAR x y)
(RULES
  plus(x,s(y)) -> s(plus(x,y))
  plus(x,z()) -> x
)

(COMMENT
Termination is shown by KBO with weight

  w0 = 1
  w(plus) = 0
  w(z) = 1
  w(s) = 1

and precedence:

  plus > s > z
)