According to an article on ESPN.com, on this day in 1993, the Colorado Rockies pulled off the worst trade deadline swap in franchise history. In the move, Colorado sent pitchers Andy Ashby and Doug Bochtler plus catcher Brad Ausmus to the San Diego Padres for pitchers Bruce Hurst and Greg Harris. As the article points out, the Rockies traded way players who combined for a future WAR of 42.3 while acquiring two players who would post a -2.5 WAR for the Rockies.
Hurst pitched in just three games for the Rockies while Harris went 1-8 in 13 starts and gave up 88 hits in just 73.