ST. PAUL, Minn. (AP) — A teacher who was assaulted by a student at a St. Paul high school plans to file a lawsuit against the school district for failing to provide a safe workplace.

The Central High School teacher, John Ekblad, says he suffered a traumatic brain injury Dec. 4 while trying to break up a fight. A 16-year-old student, who's accused of slamming Ekblad against a wall, choking him and then slamming him onto the floor, pleaded guilty Friday to felony assault against Ekblad.

Ekblad says still suffers from headaches and vision problems as a result of the attack. He says he's had to return to the hospital numerous times and is unable to work.

A St. Paul Public Schools spokesman declined to comment. Ekblad is expected to speak at a news conference Tuesday.