The first thing I noticed, just by looking at him compared to his teammates in the intros, it was clear that he is not really tall (listed at 6-1) and he was pretty much average height for the team. However, he had some really broad shoulders. He wasn't skinny, so while you could see him get a little thicker, he probably isn't going to pack on a lot more weight (in a good way). He is listed as a first baseman/OF, but I don't see how he fits at first, he just doesn't have the size for it. He played center when I saw him. The arm is at least okay, probably passable from what I saw. He did have an arm injury his junior year, that evidently he came back early from. Obviously I have no access to his medicals like teams would, but that may be something interesting to watch. He seemed to play really shallow out in center. He didn't get a lot of chances, but when he did, there was a ball hit basically to the left-fielder that McKinney just ran down. He used good strides along with good tracking of the ball, showing very nice range. He also showed good awareness of game situations, not false hustling when there was no reason to, backing up bases well etc. I am not sure what this means other than I don't think he is just a raw athlete running into walls not knowing how to play baseball.
McKinney's 1st at-bat was not impressive. He chased a low pitch, the first pitch, with an uncontrolled uppercut and popped out.
His 2nd at-bat gave us more of a look. He got ahead 3-0, then watched a changeup for a strike at 3-1 (a change at 3-0 seems very rare in high school), and then took an outside fastball with the runner moving to make it a full count. Then, he got under a low pitch, flying out to left softly with a 5.79 hang time, another uppercut swing (on what looked like a ball to me). At this point, we aren't seeing the bat speed, and it was another pitch hit the other way.
The 3rd at-bat was even worse. The first pitch was a fastball in on his hands, and he tried to swing at it. While the bat seemed relatively quick, he popped out to the pitcher lazily without getting any air under the ball. We quickly see some flaws in what McKinney is doing. He is too upper cut happy, which makes him susceptible to popping up, and the high pitch. He also wasn't showing a bat that was getting around on the ball, not pulling it.
I think we are certainly seeing him at his worst. He went 0-3 (and his team was shut out), but he has a .465 batting average and .629 OBP. He is usually a successful high school player. He doesn't have a lot of 0 for 3 games I am guessing. Obviously this speaks to the problems with one game looks. With this said, I didn't really see great tools or anything that screamed big leaguer or first round pick.
He didn't really seem to be 1st round pick size, but I wanted a more concrete look. There were 14 outfielders drafted in the first round last year (including the supplemental round). Just going by listed size, which can be deceiving, the average outfielder was about 6 feet 1.79 inches. Barrett Barnes was exact same listed size, weight and height, as McKinney. Victor Roache was same listed height, but much bigger weight wise. James Ramsey was shorter, and 3 players were listed at 6-1 and less than 195 (including Byron Buxton). So he wasn't as small as far as listed size versus normal first rounders as I thought. Of course, size doesn't matter if he has elite speed, and I know high school stats are often incomplete or misleading, but he just has 5 stolen bases, which seems low. I didn't get a great look at his speed, so I don't know if I can say more.
I obviously wished I got better video, and I wish I got a better look at him on a whole. So, below, I am posting a video of McKinney taken by Steve Florindo (here is his Google Plus Page)
In the video, I see a little hitch to get the swing started and some definite upper cut in the swing. This is all fine as a whole, but he is going to struggle with up and in good fastballs. It is a significant hole in his game. It can be really easy to find flaws in high school players games, even the really high rated ones, but to me, it is a significant flaw, and I didn't really see the great tools around it. I am not as high on him as others it is probably safe to say.