"Best pitcher in baseball" is a phrase that is bandied about more than shuttlecock at a badminton tournament. Remember when Johan Santana was the best? What happened to him anyway? Remember when Ubaldo Jimenez was the best? Flamed out near the end of 2010 and is having a rocky 2011. Remember when Zack Greinke was the best? Hasn't come close to his 2009 dominance. Remember when Felix Hernandez was the best? Not quite as dominate this year. Remember when Josh Johnson was the best? Can't stay healthy enough to deserve that tag. Remember when Tim Lincecum was the best? He's come back down to earth (possibly because he's not as high). Remember when Jered Weaver was the best? We'll see how long this lasts. Remember when Justin Verlander was the best? Great stuff, but still no Roy Halladay. The list goes on, and there will likely be new names to add to it before season's end.
Other pitchers are fads or flavors of the week. They do not stand up to the test of time like Roy Halladay does. Other pitchers have great months, half seasons, and sometimes even entire years, but they still pale in comparison to Doc. This isn't opinion, it's fact. I'm not suggesting these other pitchers are slouches (far from it), rather I'm merely stating Roy Halladay is the best pitcher in baseball.
Run the date back to the start of the 2008 season (oh, what a mighty fine year that was) and there is clearly no better pitcher in baseball over that span than Roy Halladay. He has strung together 3.5 seasons of dominate baseball: 68-34, 115 GS, 863 IP, 120:756 BB:K ratio, 32 CG, 10 SHO, 2.63 ERA, 1.07 WHIP, 25.8 WAR.
Pitchers with 20+ WAR since 2008:
1. Roy Halladay - 25.8
2. Cliff Lee - 24.2
3. Tim Lincecum - 23.4
4. CC Sabathia - 22.5
5. Justin Verlander - 21.6
6. Zack Greinke - 21.4
7. Dan Haren - 20.2
Halladay's wins, innings, ERA, WHIP, complete games, and BB:K ratio are also tops in baseball since the beginning of 2008.
*Stats provided by FanGraphs