Rafael Soriano hopes to return Monday

BALTIMORE -- New York Yankees setup man Rafael Soriano did not pitch in his regular spot in the eighth inning on Sunday because of a strained lower back. Soriano thinks he could be able to pitch as soon as Monday when the Yankees host the Chicago White Sox.

"I don't think it will be serious," said Soriano after the Yankees 6-3 win over the Orioles in 11 innings. "We'll see what happens on [Monday.] I'm going to play catch and see what happens. I'll do my regular routines."

Soriano said he first felt the back hurting on Saturday. He added he has never had back problems before.

Yankees manager Joe Girardi went to David Robertson in the eighth and he struggled, putting runners on the corners with two men out. With the Yankees up by one, Girardi turned to Mariano Rivera to try to get the four-out save. Rivera, who hadn't pitched since Tuesday, blew his second save in a row.

Soriano said he feels "better." On Sunday, in an effort to see if he could go, he played catch.

The Yankees acquired Soriano this offseason in what was a controversial signing. General manager Brian Cashman was against allocating big money for a setup man. However, Cashman was overruled by team president Randy Levine and the Steinbrenners and the Yankees signed Soriano.

On the season, Soriano is 1-0 with a 6.48 ERA in 8 1/3 innings.

Andrew Marchand covers the Yankees for ESPNBoston.com.