Every very tall hard-throwing lefty gets wish-comped to Randy Johnson. But nobody is Randy Johnson.
In the minor leagues, not even Randy Johnson was Randy Johnson.
A high school athlete from Walnut Creek, California, Johnson was drafted in the fourth round by the Atlanta Braves in 1982. He did not sign, choosing instead to attend the University of Southern California, where he played basketball and baseball. His potential was higher on the diamond, but inconsistent command kept him from being drafted in the first round when eligible in 1985. He went in the second round to the Montreal Expos, who felt that refinement and maturity could solve his mechanical issues and problems with command.
Johnson made his pro debut that summer in the New York-Penn League, throwing 27 innings for Jamestown. He was terrible, posting a 5.93 ERA and a very poor 21/24 K/BB ratio. As a 6-foot-10 hard-throwing lefty, his potential was obviously enormous, but his command was so poor in short-season ball that it was a very open question if he would reach that potential. Given his draft slot and tremendous raw talent, but with a very rough performance debut and serious command problems, he'd likely rate as a Grade C+ at the time, with a wide range of possible outcomes.
Johnson moved up to West Palm Beach in the High-A Florida State League for 1986. He improved enough to post a 3.16 ERA against tougher competition, fanning 133 in 120 innings and allowing just 89 hits. He also walked 94 men and threw 13 wild pitches. His command was better than it had been in the NY-P, and with a 95-100 MPH fastball and a nasty slider, he often dominated. Control was still an issue, but the K/IP and H/IP marks were very solid. It would be easy to slap a retrospective B+ or A- on him since we know how things panned out, but you could also make a case at the time for a straight Grade B or even a B- if you were really paranoid about his control.
Continuing his upward progress in 1987, Johnson made 24 starts for Double-A Jacksonville, pitching 140 innings with a 3.73 ERA and a 163/128 K/BB ratio with 100 hits allowed. By this point he had made a real name for himself in the prospect world (such as it existed back then) with his incredible stuff, but the walk rate remained very high and Double-A hitters often took advantage. Again, you could make a good case for any grade between A- and B-.
The first time I saw Johnson pitch in person was in 1988 for Triple-A Indianapolis in the American Association. I remember this clearly because I remember my father asking me who the "giant" on the mound was. I also remember Johnson throwing in the upper-90s that day, but also bouncing his breaking ball in the dirt, walking four or five hitters, and looking like a thrower, not a pitcher.
He made an impression; I remember telling my dad something like "this guy will be really good if he ever throws strikes, but I don't think he'll ever do that consistently." I remember thinking that maybe he would become a closer if he couldn't throw more strikes.
Johnson posted a 3.26 ERA in 113 innings for Indianapolis, fanning 111 but walking 72 and giving up 20 wild pitches. Promoted to Montreal, he made four starts, going 3-0, 2.42 with a 25/7 K/BB in 26 innings. I remember looking at that K/BB ratio in the majors and thinking "hmm...maybe he figured something out."
Or maybe not. It was a small sample. Grade B? B+? You make the call.
Johnson made six starts for the Expos in 1989 and got clobbered, posting a 6.67 ERA in 30 innings with a 26/26 K/BB, undone by command problems. Montreal shipped him to the Seattle Mariners in late May as part of a trade for Mark Langston (who was also a fascinating pitcher). With nothing to lose, the Mariners put him in the rotation and let him work his troubles out. He went 7-9, 4.40 with a 104/70 K/BB in 131 innings.
It took time. Johnson led the American League in walks three years in a row, 1990 through '92. He'd have amazing games; he'd have poor ones. For three years he was a slightly above average pitcher (ERA+108, 103, 105), eating 200+ innings per season but never quite getting over the hump to greatness.
But he tempted, oh, he tempted.
Then it happened: everything clicked in 1993. He won 19 games, posted a 3.24 ERA, led the league with 308 strikeouts. His BB/9 ratio dropped from 6.2 to 3.5, without any loss in strikeouts. His WAR shot up to 7.1.
That would be a career year for most pitchers, but it wasn't for Johnson. He just kept improving, winning five Cy Young Awards, making 10 All-Star teams, leading the league in ERA+ six times. He began to lose velocity with age, but as that happened he simply sharpened his command. At age 40, he posted a 290/44 K/BB.
Nobody would have believed a 290/44 K/BB was possible for Randy Johnson when he was walking the New York-Penn League. Hell, 140/44 would have been an extraordinary, impossible to believe projection.
Overall, he went 303-166, 3.29 ERA in 4135 innings, with 4875 strikeouts and 1497 walks, ERA+135, career WAR 114.7.
The Sim Score list: Roger Clemens, Tom Glavine, Tom Seaver, Bob Feller, Jim Palmer, Lefty Grove, Bob Gibson, Steve Carlton, Mike Mussina, and Bert Blyleven. But guys like Johnson break the old Bill James Sim Score method; he's an archetype. His WAR ranks fifth all-time among pitchers.
Comps for Randy Johnson are pointless, really.