There is a lot of scientific stuff in the article about spin and the smooth part of the ball and the seams. The bottom line, it seems, is that Garcia at times throws a pitch that moves in the opposite way normal versions of the split-fingered pitch should move. According to the article, one physicist spent hours looking at the pitch frame by frame from video and even wrote a scientific paper about his findings. That link can be found within the article noted.
The article and the findings by the physicists does perhaps explain how Freddy Garcia can strikeout 6.2 major league batters per nine innings despite having absolutely nothing on the ball and a fastball that, on a really good day, can reach 87 miles per hour. Getting swings and misses is more than just speed. It is also throwing a pitch the batter does not expect with movement the batter cannot detect. The article quotes Chris Stewart and Russell Martin and they confirm that Garcia does throw this remarkable pitch with somewhat regularity. Perhaps it is the only reason Garcia can still occasionally get major league batters out.
The article is highly recommended. Go read it and perhaps gain a little appreciation for Freddy Garcia. Lord knows, watching him pitch every fifth day with his 1.417 WHIP and his 86 ERA+ and his 5.00 ERA doesn’t glean us much cause for amazement. Perhaps we were all approaching Freddy Garcia the wrong way. We should be spending a couple of hours watching one pitch instead of watching the hundred other ones we must endure every fifth day.