I did a Retro of Oswalt in 2005, and of course the historical background remains the same.
Roy Oswalt was drafted by the Astros in the 23rd round in 1996, from high school in rural Mississippi. Scouts were aware of his arm strength, but many teams were skeptical about him since he is not a tall pitcher. He went to Holmes Community College, then signed as a draft-and-follow the following spring. He made his pro debut in '97, going 1-1, 0.64 in 5 starts in rookie ball (28/7 K/BB in 28 innings), then 2-4, 4.53 in 9 starts in the New York-Penn League (44/15 K/BB in 52 innings). This was before I did much work on short-season players, and he was not in the '98 book. Retrospectively, I would have given him a Grade C or C+ due to his K/BB ratio.
Oswalt split '98 again between the Gulf Coast League and the NY-P, and again he pitched well. He went 4-5 but with a 2.18 ERA in 11 starts for Auburn, with a 67/31 K/BB, allowing only 49 hits in 70 innings. I put him in the book, without a letter grade, but with the notation that he could "come on real quick" in '99.
He did just that, going 13-4, 4.46 in 22 starts for Class A Michigan. Now, you look at the 4.46 ERA and think "that's not that great," but in this case his W/L record was actually more representative of how well he pitched. He posted a strong 143/54 K/BB in 151 innings. I gave him a Grade C+ in the '00 book, but again praising him as a sleeper to watch.
Oswalt broke through in '00, starting off 4-3, 2.98 in 8 starts for Class A Kissimmee, then going 11-4, 1.94 with a 141/22 K/BB in 130 innings for Double-A Round Rock. "Buy Roy Oswalt stock," I wrote in my book for '01, giving him the coveted Grade A rating and ranking him as the ninth-overall prospect in the game. Among RHP prospects, I ranked him 4th, behind Ben Sheets, Josh Beckett, and Jon Rauch.
Oswalt began '01 in Triple-A, posting a 34/6 K/BB in his first 31 innings and earning a trip to Houston, where he went 14-3, 2.73 in his Major League debut. He has been one of the best pitchers in the National League ever since.
We now have an additional five years of data to look at. Looking at comparable pitchers, here are some names through age 31.
SIM SCORES: Roy Halladay, Tim Hudson, Mike Mussina, Bret Saberhagen, John Candelaria, Don Newcombe, Jim Maloney, Bob Welch, Dizzy Dean, and Andy Pettitte.
PECOTA Comps: Freddy Garcia, Jon Lieber, Kevin Millwood, Bronson Arroyo, John Smiley, Mike Boddicker, Jimmy Key, Charlie Liebrandt, Doug Drabek, and Ted Higuera.
Comps are all over the map, with the Sim Score list looking more impressive and, I think, more accurate. Everyone on this list was a fine pitcher (at worst), though their styles differed greatly.
Oswalt currently stands at 142-78 (.645), 3.22 ERA, 135 ERA+, with a 1562/436 K/BB in 1896 innings so far, 1832 hits allowed. Currently 32 years old, he is about 40% of the way to a Hall of Fame path. His "Black Ink" total is 13; an average Hall player finishes at 40. Gray Ink is 112; the average HoF is 185. His Hall of Fame Monitor rating is 55, with an average Hall guy at 100. Hall of Fame Standards rating is 33, with an average Hall rating of 50.
If Oswalt can remain active for another five or six years at his current level of effectiveness, he'll be in the Hall conversation although not a sure-fire guy. If he fades too quickly, he'll fall short, although will still rank as one of the best pitchers of the early 21st century.
He was one of the most successful examples of the now-defunct "draft and follow" process. Note that it took $500,000 for the Astros to sign him back in the spring of ‘97, which was supplemental/early second round money back then. If he had re-entered the draft pool for ‘97, his stock with scouts was high enough for him to earn the bonus as a much earlier pick. He is also another data point indicating that "short" right-handed pitchers can indeed be quite successful, provided they have the requisite arm speed and athleticism.