3rdgen- Good point. The reason I brought up Santana in the previous post:
I was invited by a friend to a Mets-Rockies game at Citi Field in the end of August. I got BP passes to the game because my friend's dad is the bench coach for the Mets. As I was standing there watching BP I was chatting with my friend's dad and we were watching Carlos Gonzalez playing pepper with the bleachers. I made a comment about how unbelievable his swing was and he pointed at Ike Davis, who stood about 15 feet away, and he said "Cargo and Ike have similarities about them in their approach in that they hit LHPs just as well as RHPs. A lot of the top left-handed hitters in the game, like Cano, Hamilton, Votto, Gonzalez, have batting averages as good or better against LHPs as they do against RHPs." I asked why and he said that he's noticed that LHPs very rarely go inside against LHHs unless its hard. Good LHHs are able to realize this and adjust accordingly. They'll understand that the only offspeed pitch they'll see from a LHP is away, and if they read a pitch in, they are able to pull their hands in and turn on the ball because its almost always a FB.
I watched Cargo and Todd Helton take a few swings a piece, and noticed how closed off their hips were and how they let the ball travel so well. I began to think about a lot of the LHHs that we consider to be the best in game, and how many of them tend to "dive" over the plate (Cano is a good example of this). I turned to my friend's dad and asked him how, as an LHP, to offset this, and he called Johan over. Johan said to throw a changeup down and in to a lefty. I kind of gave him a puzzled look (conventional wisdom and past instruction has indicated to me that you should never throw a changeup inside). Not wanting to push the issue with Santana, I continued the conversation with my friend's dad, who I assumed had similar kind of knowledge being the team's bench coach. He explained to me that an inside changeup could be a very dangerous pitch because if you miss a spot, "they'll hit it a long way". But he said that if you can locate the changeup in a pitcher's location (I interpreted this as being just below the kneecap on the corner or a few inches in), then it would be very effective. A batter will read the spin out of your hand and time their swing as if the pitch were a fastball, but in reality the pitch is diving inwards and slower. He also said that the pitch doesn't need to be thrown more than 2 or 3 times, just enough that the opponent knows you are willing and able to throw it. Therefore the next time you try to come inside with a fastball, the split second that the batter will spend with the subliminal thought that it could be a changeup could be a difference maker in the point of contact he will make.
I've tried to execute this in my own pitching, and have had mixed results. The few times that I miss the spot, the consequences are suffered. During the fall season at my school, I hit a few LHHs with changeups in the foot. I also gave up a LONG home run on a changeup that floated too much over the middle of the plate. But the few times I threw this pitch in the right location have proven to have great results. Most of my teammates that I tried this against commented that the most they'll do with that pitch is foul it off and it's a good pitch for a sequence.
In short, location and arm speed, as stated, are crucial to have a good changeup. At all levels, a good changeup can be an absolutely lethal pitch to have as part of a pitcher's arsenal because of the qualities of deception it presents to the oppsing batter.