The basics: Rodon, 21, is built more like a linebacker than a Pitcher at 6'3", 230lbs. Last season he was a workhorse for NC State. He went 10 innings of 1 hit ball in the ACC Championship game. He pitched on short rest in the College World Series and he frequently went deep in games. There's a bad reputation for Pitchers from certain schools due to overwork injuries (Rice and at one time Texas), but I have less concern about this for Rodon given his frame.
Rodon is currently a mostly 2 pitch player. He has a Fastball he throws 92-95 (though I've seen it as high as 97 and as low as 91, though some reports have it going as low as 89). He backs that up with a Slider that could already be among the best in baseball(BA calls it a curve, but having seen it, I believe it's more slider than Curve, as the break is close to 2-8, as opposed to a Curve break). He also has a Changeup, that he just hasn't really needed to bother with much against College hitters, but unveiled it last summer with USA Baseball, where he went 17 innings, allowing no runs. If he can carry the mastery of that Changeup into 2014? Well, the Astros will be mighty happy they were so awful last year. Rodon's pitches would likely grade to a 65 Fastball, 70 Slider and 50 Change, his command is probably ~70 as well, so everything plays up a notch and the Change has potential to be a 60+ pitch as well. That is dominant potential, and the Change will help keep Right Handers from teeing off on the first 2 offerings.
Video time. First, the joy of watching Rodon make hitters look silly with Sliders (and 3 Fastballs). Not much to analyze here, but watch the break of these pitches and how badly he fools guys who pretty much know a Slider is coming. On the fastballs, the Cathcer barely needs to move his glove for the catches (Video from USA Baseball)
The First 2 minutes of this video, from the great Mike Newman, is usefull for mechanics, but the angle is too high to see the pitch in the zone to determine break. The last minute+ are good for mechanics from the side. There's a lot of effort in his delivery and I wish he didn't straighten his front leg when he releases, but his arm action is very clean and consistent.
When Rodon mixes his pitches well, as he did late in the season last year, virtually no one makes good contact off him. When he doesn't? Well, here's a fangraph article with some Sliders, including one that may still be airborn.
Rodon's command doesn't look very plus in this last clip (from alskor), but he did go through a rougher stretch mid last season when his command waned a bit, this may have been during that stretch. You do get to see him working the zone though starting high, before dropping a slider in the dirt, followed by a fastball outside, then a fastball more middle in. He then works back outside, before dropping another slider in the dirt that the hitter doesn't fall for on a full count. You can also see just how often he works down in the zone, frequently just nipping the bottom of the zone with Sliders for Strikes. His command wanes though and when you nibble that much around the edges, you're going to risk walks, which Rodon sees here.
Rodon isn't without flaws (who is?), but his flaws should be correctable with minor tweaks and coaching. Thank god, he'll be in the AL.