Per an ESPN report, Sparano was in the hospital overnight Thursday after complaining of chest pains. Sparano’s wife reportedly found him unconscious in their home Sunday morning, and efforts to revive him were unsuccessful.

Sparano was an NFL assistant coach for eight years before 2008, when he was hired by Dolphins then-executive vice president of football operations Bill Parcells to replace recently fired head coach Cam Cameron following a disastrous 1-15 season. Sparano’s 2008-2009 Dolphins put together one of the unlikeliest seasons in memory, finishing 11-5 that regular season and becoming the first team in NFL history to win its division in the year immediately following a one-win season. But it would also be Sparano’s last winning season as a head coach—the Dolphins missed the playoffs in each of the next two seasons, and Sparano was fired mid-season the following year, with the Dolphins stuck at 4-9. Sparano got one more crack at head coaching, in 2014, when he was promoted to interim head coach in Oakland following the mid-season firing of Dennis Allen.

Sparano’s time as an NFL coach will be remembered for the various jobs he held as a part of the Bill Parcells coaching tree, and for that time he and his reeling Raiders team buried a football in Oakland to symbolize the turning over of a new leaf, and promptly lost six consecutive games. Sparano was just 56 years old at the time of his death.