MINNEAPOLIS — A shortage of substitute teachers is putting Minnesota schools in a bind.

As school districts struggle to pull in substitutes, teachers are heading to class sick. Principals are splitting up children between classrooms or even taking up teaching duties, the Star Tribune reported. It’s a problem nationwide, driven by more substitutes finding permanent work while other teachers leave the field entirely, drying up the pool of retired teachers that pinch hit when needed.

In Minneapolis, the substitute teacher pool is 516 this school year — down more than 60 from last year.

“It’s a crisis,” said Duluth teacher Bernadette Burnham. “It’s another layer of stress for everybody.”

The shortage has had compound effects. It’s prevented some teachers from attending professional development days, while also putting extra pressure on teachers to show up every day.