Young suffered the injury during the fourth inning on Sunday at Colorado, where he struggled through four innings, allowing seven runs on nine hits in a no-decision.
This will be Young's second stint on the DL this season. On May 22, he was placed on the DL with a nasal fracture and laceration to his nose after being struck with a comebacker in the third inning of a May 21 game against St. Louis.
"It's been a frustrating couple of months for him," said Padres manager Bud Black. "Obviously with missing time due to the broken nose and the complications from the broken nose, and now this. But hopefully, this will be just a minor setback. According to what the doctors say, this will heal and he'll be able to jump right back in."
Young is 4-4 with a 4.74 ERA over 13 starts this season.
Also Thursday, the Padres activated Brian Falkenborg, who was claimed off outright waivers from the Los Angeles Dodgers on Wednesday.
This won't be the first time Falkenborg has suited up for the Padres. In 2005, he went 0-0 with an 8.18 ERA in 10 appearances.
In 16 outings for the Dodgers this season, Falkenborg was 2-2 with a 6.17 ERA.
Falkenborg will be used in the bullpen, leaving an open spot in the rotation in the void of Young. Black said that the team will more than likely call up a starter from Triple-A Portland because he doesn't think there is anybody internally in the bullpen who can make Young's next start.
Ronald Clark is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.