Tony Gwynn was drafted by the San Diego Padres in the third round of the 1981 draft, out of San Diego State University. Assigned to Walla Walla in the Northwest League, he hit .331/.415/.612 with 12 homers and 17 steals in 42 games, showing excellent plate discipline. Promoted to Double-A Amarillo in August, he hit .462 with a .725 SLG in 23 games. Coming out of college, he was a respected line drive hitter with good speed and plate discipline, but his pro debut was much stronger than even his backers anticipated. I think you'd have to rate him as a Grade B+ prospect considering his early performance.
Gwynn moved up to Triple-A to begin 1982, hitting .328/.365/.443 in 93 games with 14 steals for Hawaii in the PCL. Promoted to the majors, he hit .287/.337/.389 with eight steals in 54 games for the Padres. At this point, Gwynn was seen as a leadoff guy due to his speed and contact hitting ability, but there were doubts about his power. It was also unclear if he'd be a .280 hitter or a .300 hitter.
He hit .309 in 89 games for the Padres in '83, then broke out with his first batting title in 1984, hitting .351. Seven additional batting titles, five Gold Gloves, and 3,141 hits followed, getting him into the Hall of Fame easily.
Most Comparable Players: Zack Wheat, Rod Carew, Paul Waner, Wade Boggs, Sam Rice, Roberto Clemente, Heinie Manush, George Sisler, Al Oliver, and Sam Crawford. Nine of those are Hall of Fame guys, the only one who wasn't was Oliver.
Gwynn hit .338/.388/.459 in his career, for an OPS+ of 132, WAR 67.9. His three best overall OFFENSIVE seasons were 1994 at age 34 (OPS+169, WAR 4.1), 1987 at age 27 (OPS+158, WAR 7.6), and 1997 at age 37 (OPS+156, WAR 4.5). However, when you factor in defense as WAR does, his 1984 and 1986 seasons rank as his second and third-best campaigns, with WARs of 6.4 both years. He hit better in '94 and '97 than he did in '84 and '86, but his defense was much better back then, boosting his WAR values. All methods show 1987 as his best season, a classic Age 27 peak.
Could this kind of career be foreseen in his minor league record? It was clear from an early point that he was a very skilled line drive hitter, and his early pro performance was outstanding. But did anyone actually project that Gwynn was a Hall of Fame talent when he was in college, or when he was in the Pacific Coast League in 1982? No. The general consensus that I remember back then was that Gwynn was seen as a guy who would be a good regular and someone who'd hit .280-.300, but he wasn't seen as a possible Hall of Fame type when he was a prospect.