Free agency is not just a major league thing, since minor leaguers can also shop their services after six years as a pro. The Cubs had almost 20 players scheduled to become MiLB free agents today, which they could avoid by placing said players on the 40-man roster.
Colin Rea looked to be a certainty for that designation and was in fact the only potential free agent to be rostered by the 5pm ET deadline. He had a good year at Triple-A Iowa, earning Pacific Coast League Pitcher of the Year with a 3.95 ERA that ranked second in the league.