High school show around 1980

I'm trying to remember a one season high school tv show that came out around 1980 about a loner who returns to school after a mysterious disappearance and is shunned quite a bit by students and faculty. In one episode someone breaks a student's rear window, and the loner gets blamed eventually and a fight ensues. The loner student gets suspended but later resolves the situation by repairing the window. He later admits he was picking lettuce somewhere when he was away.