Padres RHP Mat Latos has sore right shoulder

San Diego Padres pitcher Mat Latos has a sore right shoulder, costing him a chance to start on opening day.

Hours after he said Latos would miss his final scheduled start of the spring, Padres manager Bud Black announced Friday evening that Tim Stauffer will get the ball when the season opens next Thursday against the St. Louis Cardinals.

Latos said Friday his shoulder had improved significantly in the past 24 hours, but he won't take his next spring training turn Saturday.

Black said Latos complained of a sore shoulder and skipped Wednesday's bullpen session, two days after making his last start. Latos threw 90 pitches in four-plus innings against the Chicago White Sox on Monday, allowing three earned runs on eight hits and three walks.

Latos had increased mobility in his shoulder Friday after the team's medical staff spent Thursday treating what it identified as an inflamed bursa sac.

"From what it was yesterday, it's literally night and day," Latos said. "Yesterday it felt like everything locked and as if there was a huge piece of glass or something sharp inside my shoulder. There was no strength to lift it."

The injury caught Latos by surprise because he felt as good as he had all spring in Monday's start and again while playing catch on Tuesday.

"For me to not feel a pinch or anything and one day my arm is dead is weird," he said. "Bewildering."

Before the injury, Black had not announced an opening-day starter — but the 23-year-old Latos had been in line to pitch. Black said the injury "just popped up" and the team will see how it plays out.

With Latos on the mend, Black chose to award Stauffer with the opening-day start.

The team's first-round pick in the 2003 amateur draft, Stauffer missed the 2008 season after undergoing surgery to repair a torn labrum in his right shoulder. He made 14 starts in 2009 but began the 2010 season as a long reliever in the bullpen after Latos beat him out for the final spot in the rotation.

Black praised Stauffer for his versatility in 2010 as he finished the season 6-5 with a 1.87 ERA in 32 appearances, including seven starts. Stauffer moved into the rotation in September and provided the Padres with a boost as he went 3-3 with a 2.10 ERA in six starts.

"It's as good as I've felt physically since I've been in pro ball," Stauffer said. "I was pretty surprised, grateful and honored to get the opportunity. It was nice to hear that."

Aside from missing an outing with a hip flexor this spring, Stauffer has been the Padres' steadiest starter. He is 2-0 with a 3.66 ERA in a team-high 19 2-3 innings.

"I really like the way Stauff has thrown the ball this spring," Black said. "It has dovetailed with the way he threw at the end of last year."

Latos was 14-10 with a 2.92 ERA in a career-high 31 starts last season and finished tied for eighth in NL Cy Young Award voting. The right-hander lost his last five starts, including one on the final day of the regular season to the San Francisco Giants that knocked the Padres out of playoff contention.

Prior to his final five starts, Latos set a major league record by limiting opponents to two earned runs or less in five or more innings in 15 straight starts.

"You can't fast-forward time," Latos said. "You've just got to take your time and worry about what's going on now."

In other news Friday, the Padres released infielder Kevin Frandsen.

A non-roster invite to camp, Frandsen was trying to win a backup job. He started the spring hitless in his first 18 at-bats but batted .216 overall with one homer and eight RBIs in 37 at-bats.

Frandsen is a .243 career hitter in five major league seasons and has played for the San Francisco Giants, Boston Red Sox and Los Angeles Angels.