BALTIMORE — Mike Curtis, a hard-hitting, no-nonsense linebacker who helped the Colts win a Super Bowl during a 14-year NFL career spent predominantly in Baltimore, has died. He was 77.

Curtis died Monday in St. Petersburg, Florida. Son Clay said on Twitter his father died of "complications from CTE," a degenerative brain disease.

Curtis earned the nickname “Mad Dog" because of his fierce play in the middle of a strong Baltimore defence.

“One of the game’s most legendary non-Hall-of-Famers. Ferocious on the field, a gentleman off the field," Indianapolis Colts owner Jim Irsay wrote on Twitter.

Curtis was selected 14th overall in the 1965 draft by the Colts after starring as a fullback at Duke University. He started out with Baltimore as a fullback but rose to stardom in his second season when he played linebacker on full time.

Curtis was a four-time Pro Bowl linebacker. He had his best season in 1970, when he intercepted five passes for the Colts. Then, in the Super Bowl against Dallas, he picked off a pass in the waning minutes to set up a winning field goal by Jim O'Brien.

The following year, Curtis delivered what some believe to be his most memorable hit. When an intoxicated fan ran onto the field and snatched the football between plays in a game against the Dolphins on Dec. 11, 1971, Curtis applied a jolting tackle that sent the interloper onto the turf of Memorial Stadium.

“The way I see it, he was invading my place of business,” Curtis said.

Born in Washington, D.C. on March 27, 1943, James Michael Curtis grew up to become a fiery competitor whose reputation on the field belied his demeanour with family.

“My Dad had a tough exterior. He was a strong man, both physically and mentally, and he had a fierce work ethic," Clay Curtis wrote on Twitter. “But he had a softer side, too."

Curtis played with the Colts through the 1975 season. He played only six games that year because of a knee injury, and Baltimore subsequently left him unprotected in the 1976 NFL expansion draft.

The Seattle Seahawks snagged him, and Curtis became a co-captain for the new franchise. He finished his career with the Washington Redskins in 1977 and 1978.

Curtis played in 166 NFL games, including 131 starts. He had 25 interceptions and scored two touchdowns.

Bill Curry, a teammate of Curtis’ on the Colts, said on Twitter: “Mike Curtis was my roommate for 5 years, one of the great players ever. In my 1st camp my wife went into labour at 5am. I panicked, but Mike talked me through plane res, seeing (coach Don) Shula, and gave me the keys to his brand new T Bird. I never forgot.”

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