New York Yankees Duncan's slugging percentage was .410 with the
Staten Island Yankees in 2001. He played outfield for the
Greensboro Bats in 2002, where he had a .375 on-base percentage and 10 assists from the outfield in 69 games. Playing with the
Tampa Yankees of the
Florida State League in 2004, Duncan hit 19 home runs in 424 at bats. While with the Yankees AAA team, Duncan had 25 home runs, second in the International League at the time he was called up, and hit .295 with a .577 slugging percentage in 336 at-bats. The next day, he hit his first major league home run against the Devil Rays, and the following day had his first multi-home run game, going deep twice in front of the
Yankee Stadium crowd. Duncan later hit his fourth Major League home run at Yankee Stadium on July 31, 2007, against the
Chicago White Sox. He spent time in 2008 with both the major league Yankees, and the Scranton/Wilkes-Barre Yankees, before suffering a shoulder separation. Duncan remained in Scranton/Wilkes-Barre for the remainder of the season. He was
designated for assignment that offseason, but cleared waivers and remained in the Yankees organization. On July 31, 2009, Duncan was recalled from Scranton/Wilkes-Barre temporarily as an extra bat. He was optioned the following day and recalled again on September 7. In each of his three starts, he went 1-for-3 and recorded one RBI. Duncan was named the
International League Most Valuable Player for 2009 leading the league in home runs and RBIs. Following the 2009 season, Duncan was outrighted to Scranton/Wilkes-Barre, but refused the assignment and elected to become a
free agent.
Cleveland Indians On January 4, 2010, Duncan signed a contract with the
Cleveland Indians. He began the season with the Triple-A
Columbus Clippers. The Indians designated Duncan for assignment on August 29, 2012. In 81 games with the club during the 2012 season, he hit .203 with 11 home runs and 31 RBIs.
Tampa Bay Rays On January 22, 2013, Duncan signed a minor league deal with the
Tampa Bay Rays. He was designated for assignment on April 30, 2013. He declared free agency on October 11.
Arizona Diamondbacks On January 24, 2014, Duncan signed a minor league deal with the
Arizona Diamondbacks.
Cincinnati Reds Duncan signed a minor league contract with the
Cincinnati Reds on May 9, 2014. Duncan was released by the Reds organization on June 18. ==Coaching career==