But it wasn't until his start Saturday against the Dodgers when he realized that something was wrong, especially after making a pitch to Matt Kemp in the fifth inning.
"I felt something [in the shoulder area] and turned around and looked up at the [scoreboard]. It said 84 mph changeup. That's when I said something is going on."
Moseley had thrown a fastball, not a changeup, and a marked decrease in velocity only validated that he had something wrong with his shoulder. He said the pain is more in the back of the shoulder toward his armpit.
On Sunday, the Padres placed Moseley on the 15-day disabled list with what is termed a strained right shoulder. The team recalled left-handed reliever Josh Spence from Triple-A Tucson to take his spot on the 25-man roster.
Spence pitched one scoreless inning in relief on April 6 for Tucson, allowing two hits.
As for Moseley -- who allowed five runs on five hits in five innings against the Dodgers -- he expressed disappointment of having to go on the disabled list, especially so early in the season.
"I've got a million things going through my head," said Moseley, who will undergo an MRI on Monday to make sure there's no damage to the shoulder joint. "It's disappointing for me. All the work I did for my left [shoulder], I did for my right."
Moseley had offseason surgery on his left shoulder to ensure he doesn't suffer any dislocations like he had twice last season while swinging a bat in a game. He pitched well in spring and did not have any issues -- with either shoulder.
"I think it's frustrating for Dustin because he had a good spring and he was really looking forward to this year," Padres manager Bud Black said. "We hope this is a mild injury that he can come back from."