5. Chris Carpenter
There is no doubt that Carpenter could have been on top half of the list, if he had stayed healthy during his time as a Cardinal. The Cardinals signed Darth Carp in December of 2002. He would spend the rest of career, he retired after the 2012, with the Cardinals. However, he missed full seasons in 2003, 2007, 2008, and 2012. He also missed the 2004 Postseason which might have looked a little bit different with the team's best regular season starter making starts for a team which reached the World Series, but lost to the Red Sox in 4 games. Let's talk about what Carpenter did while he was healthy. In 2004 he won 15 games with an ERA+ of 122 pitching in his first full season since 2001. In 2005 he won 21 games, pitched a National League best 7 complete games, struck out 213 hitters, and posted an ERA+ of 150 with a WAR of 5.8. Carpenter won the National Cy Young Award in 2005. In 2006 his numbers declined slightly, but the Cardinals made it to the World Series and beat the Tigers in 5 games. Carp's lone World Series win that year was an 8 inning, 3 hit, 6 strikeout gem which gave the Cardinals a 3-1 series lead and slammed the door on any hopes the Tigers had of winning the Series. He missed 2007 and 2008, but returned in 2009 and pitched the best baseball of his career going 17-4 with a NL leading 2.24 ERA, an ERA+ of 182, and a WAR of 6.5. 2010 and 2011 were good seasons too, but the 2011 Postseason was the real highlight of his career. He pitched the Cardinals past the heavily favored Phillies in the Divisional Series, the Brewers in the National League Championship Series, and the Rangers twice in the World Series. David Freese won the World Series MVP, but I would like to think Carpenter was a close second.
4. Adam Wainwright
Wainwright is still active and still only 33, so it's possible if this list is revisited in the future, that he could end up as high as the second spot on this list. The Cardinals traded for Wainwright in 2004 when he was more or less a throw in from the Braves for J.D. Drew. He spent his first season with the Cardinals pitching out of the bullpen and ended up the team's closer in the Postseason when Jason Isringhausen was injured. Wainwright helped the Cardinals through the 2006 Postseason and recorded the final out of the team's 10th World Series win by striking out Tigers third baseman Brandon Inge. The next season the Cardinals moved Wainwright into the rotation and the rest is history. In seven seasons as a starter Wainwright has consistently been worth 15 wins, almost 200 strikeouts, and 200 innings every season. Wainwright is not the flashiest of pitchers, and is far from overpowering, but he always seems to get the job done. He has been an All-Star three times, but has never won any other individual awards. Wainwright's best season was probably 2010 when he went 20-11 with a 2.42 ERA, 230 innings pitched, 213 strikeouts, an ERA+ of 160, and a WAR of 6.3.
3. Harry Brecheen
Brecheen was a really important pitcher for a brief time on the 1940s and 1950s Cardinals. Really his career had a dramatic fall off in 1950, but before that he had about six or seven years of really really good baseball. Brecheen originally came up with the Cardinals in 1940, but then spent the 1941 and 1942 seasons in the minors. He returned to the Majors in 1943 and split the season between the rotation and the bullpen, appearing in a total of 29 games (13 starts, 11 games finished) with a 2.72 ERA and an ERA+ of 150. He also appeared in three World Series games that season in a loss to the Yankees. The next six years after that were his best years which netted the Cardinals two World Series rings. Starting in 1944, running through 1949 Brecheen won 16, 15, 15, 16, 20, and 14 games. He won the National League ERA crown in 1948, led the National League in strikeouts, ERA+, FIP, WHIP, and posted a WAR of 8.9. After 1949 his career had a sharp decline, but Brecheen spent three more years pitching for the Cardinals and his last year with the St. Louis Browns in 1953.
2. Dizzy Dean
Dean's career was similar to Brecheen's: short, high peak, quick fall. Jay "Dizzy" Dean first became a Cardinals regular in 1932 winning 18 games and leading the National League with 286 innings pitched and 191 strikeouts. His next four seasons (1933-1936) netted Dean more than 100 wins, 3 All-Star appearances, a World Series ring, and an MVP award. His best season was easily 1934, he won the National League MVP and a World Series ring, but also went 30-7 with 29 complete games and struck out a National League leading 190 batters. In the 1934 World Series Dean went 2-1 with an ERA of 1.73. After the 1936 season, Dean would only win 29 games the rest of career, or one fewer victory than he had in 1934. He spent time with the Cubs in 1938, 39, 40, and 41 before disappearing and then reappearing for one game with the St. Louis Browns in 1947.
1. Bob Gibson
This was not really that close. While some of the pitchers on this list have had a good run for a brief period of time, Gibson was able to put together a great career that include a stretch of more than a decade of really good pitching. During his 17 year career Gibby only pitched for the Cardinals and helped the team win two World Series rings to go with his two Cy Young Awards, MVP Award, and 8 All-Star Game appearances. Gibson started with the Cardinals in full time in 1960 when he split his time in between the rotation and the bullpen. By 1961 he was in the rotation full time where he would stay until his final season as a Cardinals when he had an unsuccessful return to the bullpen. His best season was easily 1968 when he won 22 games with a 1.12 ERA, struck out 268 batters, and had an incredible WAR of 11.2. Gibson was elected to the Baseball Hall of Fame in 1981 and is rated by JAWS as the 14th best starting pitcher of all-time one spot ahead of Phil Niekro and one spot behind Warren Spahn.