ESPN.com · Jul 28, 2016
Why you shouldn't expect this trade deadline to match 2015's star power
The trade deadline wasn't always a thing. There had been deals here and there, although for a long period of time the trade deadline was set at June 15. The sport didn't want the integrity of pennant races affected by rich teams buying veteran players from cellar dwellers to help out down the stretch.
The July 31 non-waiver date wasn't established until 1986. One of the first big trades that people remember was the Detroit Tigers trading a Double-A pitcher named John Smoltz in 1987 to the Atlanta Braves for Doyle Alexander, who went 9-0 with a 1.53 ERA and helped the Tigers win the American League East. But that trade actually happened in August.