The Padres also moved starting pitcher Dustin Moseley to the 60-day disabled list, making room for Thayer on the 40-man roster. Moseley underwent season-ending surgery Wednesday to repair the anterior capsule and labrum in his right shoulder.
Padres manager Bud Black said Owings' injury has been lingering. The Padres hoped rest would help his forearm, and he didn't throw for six days before he pitched Wednesday, allowing a run in 1 2/3 innings in the 7-2 loss to the Nationals. Owings again experienced discomfort, landing him on the disabled list, Black said.
"We thought, given the rest and it popping up again, it was probably going to pop up again if he went back out there," Black said.
The Padres promoted Thayer, a right-hander who was one of the final cuts in Spring Training. He has posted a 0.00 ERA at Triple-A, striking out five and issuing two walks in 8 1/3 innings.
"I was hoping I would get a chance," Thayer said. "I liked knowing that I was one of the last guys sent down, so that always gives you hope that you'll get called up sooner or later."
Thayer owns 26 innings of Major League experience, pitching with the Mets last season, when he went 0-3 with a 3.48 ERA in 10 1/3 innings. He signed as a free agent with the Padres. He also pitched 15 2/3 innings with the Rays between 2009 and '10.
"That's the message we send to our guys when they get sent to the Minor Leagues: 'When that phone rings, and it's going to some time during the year, be the guy that the Minor League people deem to be most worthy of a promotion based on performance,' and Dale has been that guy," Black said.
Thayer drove to Petco Park from his home in Murrieta, Calif. He received word of his promotion on Wednesday night -- the Tucson Padres had the day off.
Thayer carried over his successful spring to Tucson, where he got ground balls and avoided allowing a run in the high-scoring Pacific Coast League.