SAN DIEGO -- Padres Opening Day starter Tyson Ross will not require surgery on his injured right shoulder, but it doesn't appear he'll be ready to return to the mound soon.
The right-hander, who made one start before landing on the disabled list retroactive to April 5, underwent an MRI on the shoulder, and the results reached the Padres during Thursday's game -- an 11-1 loss to Pittsburgh. Manager Andy Green said afterward that he didn't have enough information to give an exact diagnosis.
"The good news was [it's] non-surgical," Green said. "We'll take a couple more weeks, re-evaluate, see where he is. Hopefully he's back on the mound quick for us."
Ross said he felt as though he was progressing "ahead of schedule" -- until he played catch Tuesday, his first throwing session since the injury.
"It was good to get out there and play catch, but it wasn't where I wanted it to be," Ross said. "I've been rehabbing pretty aggressively and made some pretty good strides as far as strength is concerned, but it wasn't the first day of catch I was looking for."
Ross allowed eight runs (seven earned) in his Opening Day loss to the Dodgers. He's coming off a season in which he posted a solid 3.26 ERA and made 33 starts for the Padres.
Meanwhile, second baseman Cory Spangenberg also underwent an MRI, and the results revealed a mild strain in his left quad -- an injury he sustained while legging out an infield single Tuesday.
"There's some optimism that at the end of 15 days he could be back with us," Green said of Spangenberg.
AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.