That’s why he didn’t talk to a lot of people in the first season of Scrubs. The producers weren’t sure the show would be approved for a 2nd season, so they limited his speaking parts. After they got the ‘Okay’ for a 2nd season he started to branch out a bit.
Also, after a few seasons they basically stopped writing the Janitor’s lines. The scripts would just say “Whatever Niel (the Janitor) says.”
(via whyfrolic)