Manager Bud Black, meanwhile, announced before the Padres game Wednesday night that outfielder Carlos Quentin is out for the season. Quentin has been on the disabled list since July 31 with an injured right knee.
The 22-year-old Erlin has had three previous stints with the Padres this season, going 1-2 with a 7.15 ERA. In 20 starts for Tucson, he's 8-3 with a 5.07 ERA.
The 25-year-old Boxberger has had four stints with the Padres this season, going 0-1 with a save and a 3.07 ERA in 10 relief appearances. In 41 outings for Tucson, he's 2-4 with four saves and a 3.67 ERA.
Information from The Associated Press contributed to this report.