It's easy to identify a mistake with the benefit of hindsight.
The Boston Red Sox never should have sold Babe Ruth to the New York Yankees.
The Cincinnati Reds would take a mulligan on trading Frank Robinson to the Baltimore Orioles in the prime of his career.
If the Chicago Cubs could go back in time and hand Greg Maddux a blank check when he hit free agency after winning the NL Cy Young Award in 1992, they would.
And you better believe Chicago White Sox general manager Rick Hahn regrets including Fernando Tatis Jr.