User blog comment:Neowitch/700 - Breakfast at Mugiwara's/@comment-4493594-20130227131553/@comment-4493594-20130227135531

Mangareader: "Joker was still keeping the Heart seat for your sake."

Mangafox:"For your sake Joker reserved the seat of the Hearts."

Sounds to me like Law used to have the seat and Dofy didn't replace him after he was gone.