He spent 1996-1997 and 1999-2002 broadcasting Orioles games before becoming the club's executive vice president after the 2005 season, a role he held until his contract expired at the end of 2008.
Buck Showalter said he got word in the middle of Wednesday night's game.
"Mike made a point of making me feel welcomed from Day One. I always looked forward to him coming in and sitting down and drinking coffee with me, and not only talking about baseball but talking about life," Showalter said. "He was a passionate man about the Orioles and family, and he impacted a lot of people's lives, not just by the way he pitched but [as] someone our organization has always been proud of not only for the way he pitched but the way he treated people."
Orioles pitcherJeremy Guthrie, who wore Flanagan's uniform number 46, said, "I think he was so close to so many people in this organization and he has touched the lives of countless thousands of people in the Baltimore community and in the baseball world."
Baltimore Sun reporters Luke Broadwater and Jessica Anderson contributed to this article.
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