The 2003 trade of Ramirez was the worst within the time I've been old enough to follow Pirates' baseball (about the late 1980s or so). If was an obvious salary dump, which was amplified in its stupidity by the fact Ramirez was not making, or set to make, THAT much by MLB standards of the period.
The Pirates had Ramirez under control for, I believe, three more years at the time. The trade, especially given what they got in return, made absolute zero sense at the time.
Part of me believes MLB "persuaded" the Pirates to make the trade, as one of its darlings in the Cubs were a contending team who had a glaring need at 3B, but that's the "tinfoil hat" side of me talking.