Kendrick was drafted in the 10th round of the 2002 Major League Baseball Draft, and named the #1 prospect in the Texas League in 2005 by Baseball America, and was called “the clear standout” in a league that also featured Kendry Morales, Erick Aybar and Andre Ethier. He was named the 12th top prospect by Baseball America in 2006.
Kendrick had a one-on-one collision with actor Ben Affleck during his rookie season in the stands on the first base side of Fenway Park. On a foul ball that was hit towards where Affleck was sitting, Kendrick beat Affleck to the ball, recording the out. Fans sitting nearby booed Affleck for not taking the ball away from Kendrick. The event landed Kendrick’s picture in People magazine. In an edition of the syndicated Access Hollywood, Kendrick presented Affleck an autographed baseball for his birthday.
Kendrick hit his first home run against the Tampa Bay Devil Rays on July 26, 2006. After Adam Kennedy signed as a free agent with the St. Louis Cardinals during the 2006-2007 offseason, Kendrick made his expected move to be the new starter at second base for 2007. He batted .322 in 88 games and again batted over .300 in 2008.
Kendrick struggled in the first half of the 2009 season, batting only .239 with 4 homers, and was optioned to the minors. After returning from the minors, Kendrick hit extremely well, batting .358 in the second half with a .558 slugging percentage