Hoffman, 28, has been working his way through the minors since 2018 and has a 5.24 ERA in 30 games this season at the Triple-A level. He has four total MLB appearances; three of those have come this year, in which he has a 3.85 ERA.
Colon, 19, has a 5.83 ERA in 22 games in rookie ball (20) and Single-A (2).
Other players the Royals have acquired at the trade deadline include Braves' No. 8 prospect Lucas Braun (LHP) and Carter Holton (LHP) in a deal with Atlanta (details here), and Carlos Duran from the Los Angeles Dodgers (details here).
Meanwhile, the Phillies have added All-Star Luis Arraez (details here).