Michael Pineda (SEA) is a leading rookie of the year candidate as he owns a 6-2 record and 2.16 ERA after nine starts. He excels at all aspects of the game as a pitcher, striking out a high number of batters while allowing few walks and home runs. So far, he's accomplished this with two pitches, a fastball and a slider.
The spin view from the PITCHf/x data allows easy identification of the two pitches:
The red blob represents Pineda's fastball, while the green area indicates the slider. The location of the fastball indicates that Michael is not perfectly over the top, but his arm slot is a bit right of center which gives his fast ball a little lateral movement, but also keeps it from dropping too much. As we've seen with Matt Cain, the high fastball is tough to hit for a home run.
The slider, on the other hand, is almost perfectly straight. A proper slider is thrown with the spin perpendicular to the flight of the ball, so there is no Magnus force.* Michael gets very close to the ideal with his slider.
*Update: I want to clarify this statement. The spin of a slider is perpendicular to the spin of a fastball. The axis of spin of the slider is parallel to the flight of the ball, which is why batters see a dot as the pitch approaches.
The most impressive aspect of his slider, however, is his ability to repeat that spin:
The bullseye of the slider is quite concentrated compared to the fastball. That indicates Michael can repeat the pitch consistently, which makes it much easier for him to spot the ball where he likes. He hits the strike zone 55.8% of the time with the pitch, which is tied for the best in the league. He doesn't hang the pitch either, as batter have yet to hit a home run off it, and slug just .211 against it. For him, the slider is the perfect pitch.