[1] Westbrook made his major league debut with the New York Yankees, but was soon traded to the Cleveland Indians, where he spent ten years.

[7] On November 18, 1997, the Rockies traded Westbrook along with fellow minor leaguers John Nicholson and Mark Hamlin to the Montreal Expos for infielder Mike Lansing.

[8] The Expos assigned Westbrook to the Jupiter Hammerheads, their Class A-Advanced affiliate in the Florida State League.

[7] On December 22, 1999, the Expos traded Westbrook along with two players to be named later to the New York Yankees for Hideki Irabu.

[10] On July 24, 2000, the Yankees sent Westbrook and Zach Day to the Cleveland Indians to complete the June 29 trade for outfielder/designated hitter David Justice.

[1] In 2001, Westbrook shuttled back and forth between Cleveland and its then Triple-A affiliate Buffalo Bisons in the International League.

[10] He led the American League in shutouts (two) and hits allowed (247),[10] and induced more double plays (35) than any other pitcher in the majors.

[10] On April 13, 2007, Westbrook signed a three-year, $33 million contract extension with the Indians, which was intended to keep him in Cleveland through the 2010 season.

[10] He also saw his first career postseason action when he started Game 3 of the 2007 American League Division Series against the Yankees, his former team.

[17] The Indians went on to win the series in four games, advancing to the ALCS to face the Boston Red Sox.

On June 7, 2008, the Tribe announced that he would be undergoing Tommy John surgery and be out of action for 10–14 months, ending his 2008 season.

[26] Westbrook tested his surgically repaired elbow in the offseason, playing winter ball in Puerto Rico.

[10] On July 31, 2010, the Indians traded Westbrook to the St. Louis Cardinals in a three-team deal which also involved the San Diego Padres.

[10] On November 16, 2010, Westbrook and the Cardinals agreed to a two-year, $16.5 million deal with a mutual 2013 option and a blanket no-trade clause.

[31] On August 31, 2011, Westbrook hit his first career home run, a grand slam against the Milwaukee Brewers.

[38] On October 31, 2013, the Cardinals declined their $9.5 million option on Westbrook for the 2014 season, making him a free agent.

[39] Hampered by injuries after the All-Star break, Westbrook saw little action in the last months of the season and was left off the Cardinals post-season roster.

Westbrook used his slider on both left- and right-handed hitters, but threw the curveball only to righties and the changeup only to lefties.