Flanked by team officials, the 39-year-old first baseman of the Arizona Diamondbacks made the announcement at a news conference prior to Arizona's home game against the St. Louis Cardinals.
But first, he flashed the humor that made him one of baseball's best quotes.
"We've agreed to a two-year extension," he deadpanned. "Oh, you didn't tell them (media) about that?"
Grace said that the three-game series against the Cardinals will be his last as an active player, ending a 16-year career spent primarily with the Cubs but also featuring a World Series championship with the Diamondbacks in 2001.
"You'll no longer see me uglying up the clubhouse as a player," Grace said.
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