If you have a problem with a person, either with their results or with their behavior, fire them.
Whole review process is designed to help managers avoid making tough decisions like firing bad apples.
In Microsoft, I got one year underachieving mark, and that made huge dent on my career. It took open-minded manager (who was recent external hire) to offer me a spot in new group. After that, I did really great, got promotion and enjoy the work.
Now, tell me, how giving me bad mark helped Microsoft? It kept me in miserable state for a year and half, forced me to work with people who already said that I am failure, and I surely didn't produce much at that time.
However, next year, I (same person, working same job), got middle-of-the-road review, and was officially allowed to look for a position elsewhere... But no hiring manager will talk to me. Whenever you apply for a position inside Microsoft, first question hiring manager asks is: What are your last three/four/five review scores? As soon as any of those is 4 (in today's system), they will stop talking to you. You cannot get even informationals... Some jerks don't even want to answer your emails anymore...
Dolphin, I know you are all smart and shiny, but axe is waiting for you too... Yank-and-rank...