High rates of absenteeism at Tesla Inc.’s lone car plant in Europe have caught the attention of Chief Executive Officer Elon Musk.

The boss of a Tesla factory has defended the decision to send managers to the homes of workers on long-term sick leave. In recent weeks, a director of Tesla’s electric car plant in Germany sent managers to check up on about two dozen employees who have continued to be paid while being on sick leave over the past nine months.