The teacher needs to nut up!
Based on my 31 years in city schools: Unless this was the "last straw" in an ongoing pattern of disruptive behavior in his classroom for which he has exhausted his 'bag of tricks," he should have disciplined the kid himself and relayed the details of the incident to parents and principal, leaving it up to them to follow up or not. That way the incident is documented and if the principal wanted to make a bigger issue of it, he could. If he didn't, then it wouldn't have made the teacher appear weak or ineffective.
One of my pet peeves was seeing colleagues abdicate their own personal authority by sending a kid to the office for discipline. The more ya do so, the more ya hafta do so. In plain language: don't show your weakness, kids will take increasing advantage. When I was dept head I worked with my staff on developing the attitude of "owning" their turf (classroom and hallway outside it), by projecting confidence and implementing an escalating series of logical consequences based on severity of infraction and previous interventions. Which is not to say that purposeful over-reaction is not appropriate, but office referral, particularly in this time of the "conciliator" principal/vp is often the least effective step you can take. It should be the last resort in a well-documented chain of actions that sets the stage for possible suspension or transfer as is appropriate for the individual.
A good stern/angry chewing can often do more good than darn near anything else. I once worked with a vp ('83-'86) that had one of the lowest suspension rates in the city. Like Andy Jackson, he could turn on his temper on cue. Kids were absolutely afraid of being referred to the office because he would tear 'em a new one. However, most administrative teams I worked with since 1971 made such a friendly office environment that kids would ask to be sent there rather than deal with classroom discipline. (I also have worked on new veeps to get them to accept the fact that when kids come to the office from me or my department, they have already been through the 'easy" steps and should not start at the "bottom of the ladder" with low level consequences. The result was that when we referred kids, something meaningful happened, and they were never bounced right back to class.
James