Kolek is in High School and is already bigger than many Major League Pitchers. He's roughly 6'5" and 250 lbs. He's strong and it's not bad weight. In either of the last 2 drafts a player with Kolek's profile would have been an extremely strong contender for the first overall pick (same can be said of Rodon, Beede, Hoffmann, Aiken and maybe even Jackson). The fact that this draft is so deep makes it possible that one of these guys could easily slide to the Phillies, so it's best to cover them all. Now, Kolek is already capable of hitting triple digits on the radar gun (though he typically works mid-90's), and given his age and the fact that he hasn't gotten professional strength training or coaching it's reasonable to think there might be more to project in terms of velocity.
Kolek works on his Parent's ranch and he's very much so country strong (in order to get to travel for tournaments, it seems, his Father makes him earn it by baling extra hay). He has a big build and I've read comps to Joba Chamberlain (in terms of build, not stuff or ceiling). Scouting reports note that while big and with a strong arm, Kolek isn't very athletic. This can be a concern in terms of repeating mechanics. All that said, Kolek went about a month this season before giving up his Frist hit as a High School Senior. He's still hitting upper 90's and 100 on Radar guns this Spring, though as noted by our excellent sister blog, Crawfish Boxes (article here), Kolek had a few control issues when seen in person last week.
As a Pitcher, Kolek relies heavily on his Fastball (as do most HS Pitchers), but he also has a Slider that flashes Plus, a developing Curveball and reports of a Changeup he throws in warm ups, but I haven't seen any game reports of it. For his mechanics, Kolek is a max effort, across the body Pitcher.In the video below (courtesy Steve Fiorindino) I can't help but think he looks like Roger Clemens. He works low in the zone a lot and gets good plane though Control seems a little shakier than I'd like. This may be a case of Kolek trying to get high heat and sacrificing some control. ?He throws from a 3/4 slot and you can see his stride towards third affecting him as he leaves a lot of Fastballs to that side of the plate and when he does miss, it's to that side. His mechanics do have some consistency issues you'll see him sometimes look very clean and balanced through his delivery and other times he stumbles a bit to the first base side after release (and once on a pitch that gets away from him the other way he stumbles off towards Third Base).
This next video is a 2-for-1, as Alex Jackson is Catching, so you can see some pitch framing and receiving skills there too. Video is from the same source and I won't talk about Jackson (he's covered elsewhere and is worth readin up on as he could very well be available at #7. Much of what you see in this video is similar to the one above. Lots of working low in the zone and lot's of heat. Kolek should be a groundball machine. Another thing he has going for him is that tall Pitchers often take a while to get their mechanics together consistently. His balnce looks much better in this video.
Others are bigger fans of Kolek than I am. I'll admit, you can't teach 6'5" and you can't teach 100 mph. Still, I find other guys available with better present stuff and better present control (Rodon, Beede, Hoffman, Aiken). Beede may be a good case study here as he struggled with Command early in his College career and has really ironed out his issues of late. The same is possible for Kolek. Plus Kolek has a workhorse build that suggest his floor might be a #2/3 Starter with a strong GroundBall rate. For me, I just see a few things I'm not fond of in his mechanics and any GM will need to trust his development staff to fix the flaws and refine the secondary offerings he hasn't had to use much in High School.