Only 16 months after Arizona was granted a major league baseball franchise, the first farm club — the Lethbridge Black Diamonds — took the field.

[6] Within their first year, in 1996, the Lethbridge Black Diamonds had the best record going 50-22 before falling in the opening round of the playoffs.

[citation needed] With manager Chris Speier, they led the league in defence/pitching, with 339 runs allowed which was 102 less than the number two place,[7] and in offense, with 637 runs, which was 94 more than the next team in the league.

The second season manager Tommy Jones led the team to a 39-33 record, which tied them for third in the league with the Idaho Falls Braves,[8] but the Black Diamonds fell within the first round of the playoffs.

[citation needed] The last season the Black Diamonds were in Lethbridge they went 43-32 with manage Joe Almaraz.