The announcement comes on the same day that Gov. Mark Dayton declared Dec. 18 Joe Mauer Day throughout the State of Minnesota. Mauer accepted the honor during an event at his alma mater, Cretin-Derham Hall in St. Paul.
Mauer joins Harmon Killebrew (No. 3), Tony Oliva (No. 6), Tom Kelly (No. 10), Ken Hrbek (No. 14), Bert Blyleven (No. 28), Rod Carew (No. 29) and Kirby Puckett (No. 34) as the only players in team history to have their number retired.
The Twins, in conjunction with Major League Baseball, also retired Jackie Robinson's No. 42 in 1997.
The retirement ceremony will take place at a yet-to-be-determined game next season.
The six-time All-Star announced the end of his career following this past season, citing concern about the long-term effects of concussions and a desire to spend more time with his wife and three children.