Mickey Moniak is a 6'2" 190 lb Center Fielder from Encinitas, CA with a College commitment he is unlikely to fulfill to UCLA. He is almost certainly a Top 10 pick this year and High School or College, he may well be the best pure hitter in this draft. In a somewhat thin class he is rocketing up boards late and word is the Phillies even had noted hitting expert and beloved former Manager Charlie Manuel watch him recently in game action. Rumors are the Phillies love his hit tool and ceiling, but rumors are particularly all over the place this year, so take that with a jar of salt.
Now, it's common for all kinds of players to play Center Field and Shortstop in Highschool with no chance of playing there as a pro. Is Moniak one of those? Decidedly not. Mickey has all the tools to play Center as a Pro and possibly even be a very good defender. Depending upon which report you read his speed is either Plus or Plus-Plus. Both of those are good (to undersell things a bit). His frame can probably carry 210-215 pounds comfortably without getting rid of his speed. So he can cover ground in Center. He also brings an Above-Average to Plus arm (again, depending on reports). Radar gun speeds on Outfield throws are tricky to find for High Schoolers, but Perfect Game reliably publishes readings I have no real idea the veracity of. That said, the 89 mph reading they have for Moniak hints at a very playable arm, but not a weapon. Plenty for Center and enough for Right Field if needed.
That previous paragraph talks about the tools to play Center, but there are also reads off the bat and routes to consider and Moniak is superb Hudson Belinsky from Baseball America posted a clip with Moniak chasing down a deep fly Willie Mays style over-the-shoulder basket catch at full speed. Per that article Moniak heard the sound and saw the initial trajectory and just ran to his spot. Only looking up in time to see the ball in his glove. He appears to be doing a little more looking up than that, but it's the kind of highlight reel play that's kinda rare in High School games (so rare, that there are accounts of that catch in half the articles you'll read on Moniak). Lots of reports note how easy he makes Defense look.
His Defense is his carrying tool, but his bat has a chance to be every bit as special. Moniak has Plus bat speed and the bat control to rival anyone's if he swings he generally doesn't miss. He's a very cerebral hitter from reports and interviews. He attacks at bats with a plan and he sounds like he understands with rather professional intimacy the mechanics of his swing. The swing is a beauty. He keeps his head level even with all that rotation. Look at the video below and notice how quiet his bat is pre-swing. Likely deadly still almost. This is home run derby video, so he's selling out a bit for power, but the split screen is nice for analyzing. One flaw is he rolls his front foot, which will sap some of his power. Should be easy for a team to clean up and he doesn't do it all the time in that clip. Video from the Prospect Pipeline.
Even better below is video from the same source, but in game action not in glorified Batting Practice. No ankle role, smaller leg lift, better extension (weirdly) and just all around what you would teach a kid to do at the plate. The tools are there for a .300 hitter. I've seen report label it a 70 hit tool and even those less willing to go out on a ledge give it a solid 60 grade. Where there's still a good bit of projection is Power. Ignore Moniak's SLG this year. he's largely using his speed and gap hitting ability to leg out a lot of triples that won't be there as easily in the Pros. That's fine, he can still get doubles from the, but his slugging is probably a little inflated by his speed. Home Run Power is largely projection with him. If he adds 20+ pounds of muscle and sacrifices a little contact some reports give his Power a potential Plus grade. Some suspect it never really comes and he ends up with Average Power, so that's a range of ~15-30 Home Runs a year, which is a rather large delta.
I've seen one comp to Shawn Green (I don't see it, but okay), but I've seen lots of comps to current Marlins OF Christian Yellich. I suppose Yelich is kind of the floor if the power never develops and Green is someone's fever dream of Moniak if the power does develop. I doubt Moniak will have a 49 Homer season, but with his Speed, Defense and hitting any power is a bonus. For a High Schooler I think he's got a pretty high floor. Perhaps his floor might be pre-2016 Jackie Bradley, Jr. (and apparently his ceiling may also be Jackie Bradley, Jr., if the guy we skipped for Larry Greene keeps up his hot start). I'll just end this with THE CATCH.