David Robertson has soreness near rib cage

BALTIMORE -- Add David Robertson to the growing list of ailing Yankees pitchers.

The Yankees turned to Rafael Soriano in the ninth inning of Monday night's 8-5 victory over the Orioles at Camden Yards because Robertson was dealing with soreness near his left rib cage.

Robertson, who was expected to take over closing duties after Mariano Rivera suffered his season-ending ACL tear, said he first noticed the soreness during Friday's game and that it has lingered. He has not thrown off the mound or lifted weights since.

Robertson said he is uncertain how long the injury will take to heal.

"I don't even know what to expect," he said. "I can't really tell you if it's gonna go away in a few days or if it's fine. I don't know. I've never had an injury like this."

When asked if there is concern about the injury, manager Joe Girardi said: "There's a little bit."

Robertson and Girardi said they expected the reliever to go for tests Tuesday morning.

"I'm not really concerned," Robertson said. "I just would like to get back out there as soon as I can. I don't want to go out there and take a risk and then end up putting myself on the DL for a long period of time. So I was a little worried, but I honestly don't think it was too bad."

Robertson said there wasn't any moment that caused the injury. "It's more like when I was out there on the field, I was getting a little sore," he said. "It wasn't like one pitch that I felt something rip or tear."

Robertson has one save and one blown save since Rivera was injured May 3 in Kansas City. He has allowed an earned run in only one appearance since Aug. 29 of last season.

"It's tough because right now the pen's kind of thin," Robertson said. "Guys have been pitching a lot of back-to-back games and I haven't been able to step in and help out and pick up some innings."

Boone Logan and Cory Wade combined to strike out the side in the eighth. Then Soriano performed well in earning the save, striking out one and working around a two-out error in the ninth.

"He was good," Girardi said. "Really, really good. He came in and did a nice job for us."

Soriano led the American League with 45 saves in 2010, when he was with Tampa Bay. He said last season, when he lost his eighth-inning job to Robertson after an injury, he was concerned about closing, but no longer.

"This year I don't think about that," Soriano said. "Whatever they want me to do."