Montañez was drafted by the Chicago Cubs third overall in the 2000 MLB draft. He spent seven seasons in the Cubs' minor league system but never made it to the Major Leagues. On January 5, 2007, he signed a minor league contract with the Baltimore Orioles. After batting .335 with 26 home runs and 97 RBI in 116 games for the Orioles Double-A affiliate Bowie Baysox, he was called up to the Majors for the first time. In 2008, Montañez won the Eastern League Triple Crown despite missing nearly a month of the season after getting called up to the majors.

Montañez made his major league debut on August 5, 2008, but did not get an at-bat. On August 6, he hit a home run in his first at-bat making him the second Oriole to accomplish the feat. After starting the 2009 season playing for the Orioles Triple-A affiliate, Norfolk Tides, he was re-called to the majors on April 21 after an injury to Ryan Freel. On November 10, 2010 Montanez became a minor league free agent.

Montañez signed a minor league deal with the Chicago Cubs on January 2, 2011. He was called up from the Iowa Cubs on May 24, 2011 and was in the lineup that night at Wrigley Field against the New York Mets. His first at-bat resulted in an RBI double. He elected free agency on November 28.

...
Wikipedia