Scouts always liked him, but Brady Aiken used to be described in a series of back-handed compliments. He was “solid” and had great “pitchability”. Aiken projected as a middle-to-back-of-the-rotation starter, still valuable, but any real upside was wish-casting.

Sometimes wishes come true.

Gradually 89 MPH became 94 MPH. The movement and command remained. Aiken went from good to great. Brady Aiken has become a bonafide ace in the making.

One of the most important things in scouting is not judging any specific ability, nor even the combination of any abilities but the progress of abilites over time. Baseball players tend to peak in their late-20’s and many elite prospects are drafted a full decade before they peak. Major League teams have to project growth curves far in the future. It’s much, much, MUCH easier to project a line from a smaller line instead of a single point. Watching a player progress from good to great is better indication of future success than a player flashing great skills once.

Aiken is blessed with prototypical size, 6-foot-2, 210 pounds, and has worked himself into a terrific athlete. His arm action is short; his mechanics are simple and repeatable. His fastball boasts tremendous sink and lateral movement that should leave many a bat with unscuffed barrels, if not shattered handles. Aiken’s curve-ball is a true out-pitch and, at its best, Zito-esque. Aiken’s excellent mechanics, athleticism and feel for pitching give his command huge upside.

Aiken is virtually the complete package. Occasionally guys will throw harder, but they don’t command it as well. Occasionally they’ll command it as well but they won’t have the breaking ball. Occasionally they’ll have the breaking ball but their motions look like a washing machine with an bowling ball in it.

It’s been over a decade since a high school left-hander went in the top five picks of the MLB draft (Adam Loewen went 4th to Baltimore in 2002). The best HS LHP prospect in recent years came by way of the Dodgers when they selected a lefty with the seventh overall pick of the 2006 draft out of Highland Park High School in Dallas, TX named Clayton Kershaw. He’s been pretty good so far.

Brady Aiken is the best left-handed high school pitching prospect since Kershaw. It sounds a little crazy to compare a two-time Cy Young winner to a kid who hasn’t graduated high school yet. Most Major League comparisons for amateur players are done on the basis of physique, position and one or two skills. Are you a left-handed offensive oriented second baseman? Congrats, you are now Chase Utley. A short, left-handed pitcher with a great change-up and preferably Hispanic? The next Johan Santana. An outfielder who looks like there’s a rabid ferret in your pants during a game? We’ve just found the new Hunter Pence!

If you want to compare a prospect to a Major Leaguer based on skill at the same age of development and ultimate upside, Clayton Kershaw is the right comp for Aiken. That doesn’t mean that Aiken should start clearing space on his mantle for awards just yet but it does mean that if you want to put a comparison on Aiken you end up saying something crazy.

Worst-case scenario (not counting injury) Aiken’s stuff settles in at just “pretty good” under the rigors of a five-man rotation and he has a solid career as a quality No. 3 starter.

Best-case scenario Aiken’s fastball combines velocity, movement and command into a 70-grade offering and his curve-ball is even better, he generates tons of ground balls, whiffs and never walks anyone. In 2013 only four pitchers generated more than 50% ground balls AND struck out over a batter an inning (Justin Masterson, AJ Burnett, Stephen Strasburg and Felix Hernandez). Aiken could match those totals. He could be a true ace, one of the handful of best pitchers in the game and a perennial Cy Young candidate. He could be the next Clayton Kershaw. Brady Aiken is so good, it’s crazy.