Minnesota Vikings OL coach Tony Sparano died unexpectedly Sunday morning, the team announced. He was 56.

"Our hearts go out to Jeanette and the entire Sparano family as we all mourn the loss of Tony," Viking owners Mark and Zygi Wilf said in a statement. "Tony was a passionate and driven individual who cared deeply about his family, and especially enjoyed spending time with his grandchildren. Tony's presence within the Vikings organization will be deeply missed. We are only thinking of Tony's family during this incredibly difficult time. We ask that the entire NFL and Vikings family keep the Sparanos in their thoughts."

Sparano was admitted to a hospital Thursday after complaining of chest pains, according to ESPN's Adam Schefter and Chris Mortensen. He underwent tests and was released Friday. Sunday morning, according to ESPN, Sparano was preparing to attend church with his wife when he collapsed on the kitchen floor of their home, where he died after his wife, Jeanette, attempted CPR.

Sparano began his NFL coaching career in 1999 as Browns offensive quality control coach. His first head-coaching opportunity came in 2008, when the Miami Dolphins hired him away from Dallas. Inheriting a 1-15 club, he engineered one of the more impressive year-over-year turnarounds in NFL history, guiding Miami to an 11-5 mark and AFC East division title, the franchise's most recent AFC East championship.

But that proved to be Sparano's high-water mark as a head coach. He was fired by the Dolphins in the middle of the 2011 campaign. He served as the Raiders' interim head coach three years later, after Dennis Allen's firing, and was hired by Minnesota in 2016 to oversee the Vikings' offensive line.

Sparano was a key part of the Vikings' breakthrough season a year ago. After overseeing the NFL's most injury-riddled O-line in his first year, Sparano coached a unit with three new starters not only to respectability but made a formidable unit in 2017, when it helped Minnesota finish 11th in total offense and 10th in scoring, after 28th and 23rd, respectively, the year prior.

Sparano's football coaching career began in 1984, when he was hired by New Haven as offensive line coach, a job he held for four seasons. His first head-coaching opportunity also came at New Haven, in 1994.

Sparano served as an assistant or head coach for nine NFL clubs — Cleveland, Washington, Jacksonville, Dallas, Miami, New York Jets, Oakland, San Francisco and Minnesota.

Sparano is survived by his wife, Jeanette, two sons, Tony and Andrew, daughter, Ryan Leigh, and four grandchildren.