Colby Lewis throws a deep slider.
We know this because Tim McCarver, in his first action this postseason, said deep slider four times in the first two innings.
Now, I have to admit that I don't know what deep slider means.
He does throw a ton of sliders, roughly 27 percent of the time in both 2010 and 2011. According to FanGraphs, it was an outstanding pitch for him last season, not so much this season. Still, it's fairly safe to suggest that Lewis's slider is the pitch that got him back to the majors after two seasons in Japan, and the pitch that's made him a huge part of the Rangers' success these last two years.
Deep Slider Update: McCarver didn't say deep slider once in the third inning, but Lewis just kept pitching well.