The Chicago Cubs were burned by their 2017 trade with the Chicago White Sox, and it seems to be Jed Hoyer's determination that it never happens again. The infamous trade saw the Cubs give up their top hitting prospect, Eloy Jimenez, and their top pitching prospect, Dylan Cease, to address a massive need in their starting rotation with the addition of Jose Quintana.
The deal was made a few weeks before the 2017 trade deadline, and it effectively saw the Cubs set the price for a controllable starting pitcher. Something Hoyer's front office wasn't willing to do this time around.