Four years ago, the Diamondbacks tried to acquire a strong, hard-throwing right-handed starter from the Seattle Mariners.
Taijuan Walker was a crown jewel then, a Baseball America top 20 prospect three straight seasons starting in 2012. Every team wanted him, and the Diamondbacks thought they had him, only to be foiled when outfielder Justin Upton exercised his limited no-trade clause and refused to go to Seattle.
Walker’s star has dimmed since then. He’s 24 years old, and in parts of four seasons with the Mariners he went 22-22 with a 4.18 ERA. Hardly the stuff of a can’t-miss prospect.