Drew to the Atlanta Braves in December 2003 for pitchers Jason Marquis, Ray King, and prospect Adam Wainwright.

[9][10] Marrero hit .415 against left-handed pitchers with Atlanta in 2004, serving as a backup outfielder behind lefties Drew and Charles Thomas.

[11][12] Following the 2004 season, the Braves dealt him to the Kansas City Royals, who needed a power-hitting corner outfielder, for minor-league pitcher Jorge Vasquez.

[16] On July 2, Marrero saw his first major league action at third base, playing two innings in a blowout loss to the New York Yankees.

[21] Marrero's son Elih was a 29th round pick by the Cincinnati Reds in the 2015 MLB draft, but he elected to play college baseball at Mississippi State.

[20] Elih later transferred to St. Thomas University in Florida and was selected by the Boston Red Sox in the eighth round of the 2018 MLB draft.