Jim Bouton, author of "Ball Four", was 80.
Bouton, 80, died Wednesday at his home after "a valiant struggle with vascular dementia", the friend said.
In the early part of his career, Bouton was a hard-throwing force for the Yankees - becoming an All-Star, a 20-game victor and a World Series starter for NY in 1963. He finished his career with a record of 62-63 with a 3.57 ERA.
But it was his off-the-field actions that won Mr. Bouton his greatest fame, as "Ball Four" depicted off- and on-the-field and in-the-clubhouse antics that had previously remained hidden by ballplayers' and sportswriters' code of silence.
"You see, you spend a good piece of your life gripping a baseball, and in the end it turns out that it was the other way around all the time", Bouton wrote at the end of his book.
According to the Daily News, the controversial smash hit was the "only sports book cited when the New York Public Library drew up its list of the best books of the 20th century". Bouton also had two strokes in 2012.He had been in a years-long battle with cerebral amyloid angiopathy.
New York Yankee pitcher Jim Bouton wearing his glove and holding a baseball. Finally, the ban was lifted last season when Bouton appeared at the Yankees Old-Timer's Day game, receiving a warm ovation.
Throwing so hard that his cap often flew off his head, Bouton was 21-8 with six shutouts in 1963 - his second season in the majors and his only year as an All-Star - and went 18-13 with four more shutouts in 1964.
Bouton injured his right arm in 1965, going 4-15 that season, and saw limited action the next three seasons with NY. He worked on Ball Four in 1969 as he spent the season with the expansion Pilots and Houston Astros, his fastball replaced by a knuckleball as he tried to prolong his career.
Bouton was approached in 1968 by New York Post sports writer Leonard Shecter about writing a tell-all book, and he agreed. He pitched in two World Series for the Yankees. He joined the Braves in 1978, at the age of 39 after developing a knuckle ball and after having been out of the majors since 1970.
Information from the Associated Press was used in this report.