Harang has a sore right foot and Moseley a slight dislocation of his left shoulder.
Harang won his team-high seventh game in a 7-3 win over Washington on Thursday and is scheduled to start Tuesday night at Colorado. X-rays taken of his foot Friday were negative.
He isn't sure how he hurt the foot, but says that it has bothered him since last week.
"It just doesn't feel comfortable, but hopefully it will feel OK before my next start," he said.
Moseley hurt his shoulder batting in his last start Wednesday, and has been saying since then that he will make his start Monday at Colorado.
Padres manager Bud Black wasn't so sure Saturday.
"It looks as if he's not going to make his next scheduled start," Black said before San Diego's game against Washington.
The manager then yelled out to the field and told Moseley he had just informed the media he wouldn't be starting. Moseley smiled and said, "We'll talk."
The most likely candidate to fill in is left-hander Wade LeBlanc at Triple-A Tucson. He is 12-17 with a 4.47 ERA in 39 starts for San Diego over the last four seasons.