Plácido Enrique Polanco (born October 10, 1975) is a Dominican Major League Baseball player who has played for the Philadelphia Phillies, St Louis Cardinals and Detroit Tigers. He usually plays second base and occasionally shortstop and third base.

Drafted on June 2, 1994 by the Cardinals in the 19th round of the 1994 Major League Baseball amateur draft, Polanco was promoted to the major league level in 1998. He backed up the infield while improving himself offensively and defensively. Handed the starting third base job in 2001, his low strikeouts-walks ratio over number of at bats and extra bases hits established himself as a contact hitter in the batting lineup. He finished the 2001 season with a .307 batting average, 12 stolen bases and smacked 173 hits, 26 doubles with only 43 strikeouts over 564 at bats.

On July 29 2002, Polanco, Mike Timlin, and Bud Smith were acquired by the Phillies for Scott Rolen, Doug Nickle and cash. Polanco was shifted to second base as David Bell was signed from free agency to play third base. He began to develop power while playing for the Phillies as he hit 14 and 17 home runs in the following two years. He became a free agent player after the 2004 season and was rumored to be returning to the Phillies. The Phillies did sign Polanco for 2005 but sent him to the Detroit Tigers in June 2005 in a trade for veteran right-hander Ugueth Urbina and infielder Ramon Martinez, allowing the Phillies to play Chase Utley every day at second base. Polanco finished the 2005 season batting .338 with the Tigers, and also having a career year with regards to OPS(.847). Polanco has continued to play second base for the Tigers in the 2006 season.

Polanco is a .300 career hitter with 828 singles, 257 extra base hits, including 62 home runs and 367 RBIs in 1004 games.

Placido was a key part in the 2006 Division and Championship series for the Detroit Tigers. He was named Most Valuable Player of the 2006 American League Championship Series. However, he did not record a single hit in the 2006 World Series, in which the Tigers lost to the Cardinals in 5 games.

Polanco is close friends with first baseman Albert Pujols. The two met as teammates while playing for the St. Louis Cardinals. Pujols is godfather to Polanco's 3-year-old son, Ishmael.