When a player gets drafted into Major League Baseball from high school or college, there's always an element of guesswork at how he will adjust to and develop in the pros. The 2017 MLB draftees have mostly had their first taste of the minor leagues, so even if it's still very early in their professional careers, limited data in the low minors can tell us something about their progression.
While it's way too soon to call anyone a slam-dunk superstar or a certain bust -- struggling or succeeding in the California League is very different than doing so in the Triple-A International League or Pacific Coast League -- many of the draftees have played enough to give us at least some additional play-based insight into their future. First-round draftees tend to contain the most advanced amateurs, many of whom are expected to go through the minors quickly, so a lot of them now have enough data to start talking about relevant minor league translations and projections.
This look is at players with enough playing time in the minors so far, so no updates on players who are out with significant injuries (such as Jake Burger), have not yet made their 2018 debuts or have played only very briefly (such as Shane Baz). Projection systems need information; starved of it, they don't contribute anything to the overall view of a player.
No. 1: SS/CF Royce Lewis, Minnesota Twins
Minor league translation to-date: .241/.292/.314, 9 steals in 353 at-bats
Lewis has done little so far to suggest he's not a top prospect, and while his K/BB rate has dropped a bit from his debut, he's still hitting .299/.351/.365 in a full-season league (Midwest) and doesn't turn 19 until next week. He's younger than every person ahead of him in the Midwest League in batting average.
Perhaps even more importantly, the questions about whether he could stay at shortstop long term have not been answered in the negative. The Twins certainly aren't burning with desire to move him to center field yet, and most reports have him generally progressing. ZiPS does give rough estimations of minor league defensive performance, and while you should take small samples of defensive data far less advanced than what we have in the majors with giant truckloads of salt, ZiPS estimates Lewis as only two runs worse than average at the position to date. ZiPS sees Lewis developing power, peaking as a 100 OPS+ shortstop with 15 home runs a year.