Carlos Luis Rivero Milán (born May 20, 1988) is a Venezuelan professional baseball third baseman for the Tokyo Yakult Swallows of Nippon Professional Baseball (NPB). He has played in Major League Baseball (MLB) for the Boston Red Sox.
Rivero was originally signed by the Cleveland Indians as an international free agent in 2005, and played for them for five minor league seasons (2006–2010) before joining the Philadelphia Phillies (2011) and Washington Nationals (2012–2013) organizations. He initially began as a strong-armed shortstop before being moved to third base, and has also spent time in left field. The Red Sox signed him in December 2013.
In between, Rivero played winter baseball for the Leones del Caracas, Bravos de Margarita and Cardenales de Lara clubs of the Venezuelan League.
The Venezuelan infielder ranked among the 20-top Cleveland prospects from 2007 through 2009. He also was rated twice by Baseball America as having the best infield arm in the Indians organization in the 2008 and 2009 seasons, before being named the best defensive third baseman in the International League in 2012 while playing for Washington affiliate the Syracuse Chiefs.
Rivero earned International League All-Star honors during the 2012 season when he played at Syracuse. Previously, he was named the 2007 South Atlantic League Mid-Season All-Star while playing for the Lake County Captains, also a Cleveland affiliate.
Not long after signing him, the Red Sox assigned Rivero to Double A Portland Sea Dogs to start the 2014 season. He then gained a promotion to Triple A Pawtucket Red Sox during the midseason. He struggled after being called up to Triple-A, batting just .179 through eight games in the month of May. But Rivero improved the rest of the way, hitting .319 to go along with a .375 on-base percentage in June. He finished the month with a solid week, recording at least a hit in all seven games to be named the International League Batter of the Week. He went 12-for-28 (.429) during the seven-game span, raising his season average to .286. In addition, Rivero drove in five runs and scored six times, while compiling three extra-base hits, as his efforts helped Pawtucket conclude a 5-2 stretch. But one thing kept Rivero in the Pawtucket line-up as he often filled the designated hitter role when he was not playing on the field. Overall, he hit .262/.320/.379 with five homers and 36 RBI in 74 games for Pawtucket before joining the Boston Red Sox.
After nine seasons in professional baseball, Rivero became a major leaguer when the Red Sox purchased his contract from Pawtucket on August 25, 2014 after placing shortstop Xander Bogaerts on the seven-day concussion disabled list. He made his major league debut on August 29, pinch hitting for Will Middlebrooks. He was walked in his only plate appearance.
Rivero was claimed off waivers by the Seattle Mariners on November 3, 2014 but on December 2, 2014 he was non-tendered and became a free agent. However, they soon re-signed him to a minor league contract.
On August 9, 2015, Rivero was traded back to the Boston Red Sox for cash and assigned to Triple-A Pawtucket.
On November 18, 2015, Rivero signed a minor league deal with the Arizona Diamondbacks. He was assigned to Triple-A. Rivero signed a new minor league contract with the Diamondbacks on January 24, 2017. He was released on June 19, 2017.
On July 6, 2017, Rivero signed with the Tokyo Yakult Swallows of Nippon Professional Baseball.