Carlos Alberto Zambrano Matos (born June 1, 1981), nicknamed "Big Z" or "El Toro", is a Venezuelan former professional baseball pitcher. He played in Major League Baseball (MLB) from 2001 to 2012 for the Chicago Cubs and Miami Marlins. Zambrano, who stands 6 feet 4 inches (1.93 m) and weighs 275 pounds (125 kg), was signed by the Cubs as a free agent in 1997 and made his debut in 2001.

After being used in both starting and relief duties, he enjoyed his first full season as a starter in 2003, finishing with a 13–11 record, 168 strikeouts and a 3.11 ERA.

Zambrano is known as one of the best hitting pitchers of recent times. He was a switch-hitter with a career .238 batting average with 24 home runs, 71 RBIs and a slugging percentage of .396. The 24 home runs are the most ever by a Cubs pitcher. He also tied with Ferguson Jenkins for the club record for home runs by a pitcher in a single season, hitting six in 2006. Zambrano was called on to pinch hit 20 times in his career and won three Silver Slugger Awards for his hitting.

Zambrano was the only National League pitcher to win at least 13 games in each year from 2003 to 2008. In 2006, he became the first player from Venezuela to lead the National League in wins.

Zambrano was called up to the Cubs and pitched in his first game on August 20, 2001, starting against the Milwaukee Brewers at Wrigley Field in the second game of a double header. Zambrano started the game well, retiring nine of the first ten batters faced. He ran into difficulties in the fourth inning, and was removed before getting any outs in the fifth. He was charged with seven earned runs, walked four batters, and threw just 74 pitches.

One month later, on September 20, Zambrano earned his first big-league victory by finishing out the fifth inning against the Houston Astros. Zambrano pitched just two-thirds of an inning in relief of Juan Cruz, and was just 20 years old. He played 6 games making 1 start with a 1–2 record and a 15.26 ERA. Zambrano did not have any additional starts in the season, and the Cubs finished in third place with an 88–74 record.

Zambrano started the 2002 season at the Triple-A Iowa Cubs, but was quickly called up to the big leagues where he was dispatched to the bullpen and pitched in sixteen games during the first three months of the season. On July 1, 2002, Zambrano started against the Florida Marlins, taking a struggling Jason Bere's spot in the rotation. Zambrano logged sixteen starts for the Cubs, recording four wins and eight losses. At times he showed immense potential, including eight innings of shutout ball against the Milwaukee Brewers on September 4. Zambrano did struggle with control, logging 63 walks in just over a hundred innings of work. Overall, he finished the season with a 4–8 record and a 3.66 ERA in 32 games (16 starts). The Cubs posted a disappointing 67–95 record for the season, finishing in fifth place.

Zambrano maintained his position in the Cubs starting rotation in 2003 and started 32 games with a 3.11 ERA and 13 wins in the fourth spot in the rotation, behind Mark Prior, Kerry Wood, and Matt Clement. The Cubs won the National League Central division, and were one win away from going to the World Series before being defeated by the Florida Marlins. The following year, Zambrano improved his statistics by lowering his ERA to 2.75 and increasing his strikeout total to 188. His record was the best on the Cubs staff that year, compiling a 16–8 record.