He told evertonTV: "He's been great. The manager's heaped a load of responsibility on him by giving him the captain's armband but he's relished it. He's been a fantastic leader for us."
Howard also puts Yobo's outstanding performances down to his time with the Nigerian squad.
He added: "I think we have a few leaders in this team because the manager has brought in a heap of experience but Joseph has been captain of his country.
"He knows what it's about at the highest level and he's been fantastic in that role."