After first being called up to Chicago from Tennessee in June, Gallagher was later sent to Triple-A Iowa and was 3-1 with a 2.66 ERA in eight starts.
Hart was 4-1 with a 3.54 ERA in nine appearances with Iowa including eight starts after being promoted from Tennessee in mid-July.
Those numbers and the Cubs' decision to send both pitchers back to Tennessee hardly reek of anything resembling a demotion.
Most likely the Cubs are sending two of their best pitchers from Triple-A back to Double-A to strengthen Tennessee's chances of reaching the playoffs.
Tennessee is 34-31, 1.5 games back of first-place Huntsville in the Southern League's Northern Division. They lead the Wildcard race in the Southern League and can advance to the playoffs as long as Chattanooga (33-32, 2.5 GB) does not win the second half of the Northern Division.
Huntsville won the first half.
Before both players could rejoin Tennessee, they needed the approval from Minor League Baseball, which was granted earlier this week.
"They both need to pitch," Tennessee manager Pat Listach said. "They both need to pitch because one or both may be headed to Chicago."
Gallagher was 7-2 with a 3.39 ERA in 11 starts with Tennessee earlier this season before making his big league debut on June 9 in Atlanta.
Hart was 7-5 with a 4.45 ERA in 17 appearances with Tennessee, including 16 starts. He leads the Cubs farm system with 128 strikeouts this season.