Josh Collmenter of the Arizona Diamondbacks shut down the Brewers this season, including in Tuesday night's NLDS game. He accomplished this by working in three pitches with enough subtle differences to fool Milwaukee batters into a .116/.164/.159 slash line in 2011.
The Brewers hit Josh's fastball decently. They posted a .286/.348/.429 line against that pitch.
Notice that Josh avoids the middle of the plate with his fastball. He seldom gave the Brewers a phat pitch down the middle. Note, too, that his fastball isn't terribly fast averaging 87.7 MPH.
Josh does throw pitches down the middle of the plate, however:
You can imagine what happens here. Josh gives batters the fastball motion, and puts the ball right in the middle of the plate. He even gives the pitch the same vertical and horizontal movement as the fastball. The batters sees fastball down the middle, but the pitch comes in a 76.3 MPH, and the swing misses. The Brewers did not swing and miss at a Collmenter fastball in 2011, but they missed on 30% of swings at change ups.
Collmenter also comes at them with a cut fastball.
Collmenter's delivery is extremely overhand. When he throws his fastball, he gets nearly perfect backspin, the ball tilted every so slightly toward a right-handed batter. With the cutter, he manages to get the mirror image spin, tilted ever so slightly toward the left hander.
Again, he throws this pitch down the middle, but it moves differently, and the batters make poor contact. They miss on 15.4% of their swings, and are just 1 for 21 putting the pitch in play. Josh throws three pitches with the same delivery, but against the Brewers gets very different results.