Quintanilla, 30, was designated for assignment on Tuesday to make room for outfielder Jason Bay to come off the disabled list. Quintanilla hit .257 with a home run and four RBIs in 29 games for the Mets this season. He was drafted in the first round of the 2003 First-Year Player Draft by the Athletics.
"I'm excited about adding him," said Orioles manager Buck Showalter. "I talked to some people I know with the Mets after the fact, and they speak very highly of him. ... They didn't wanna lose him."
Quintanilla could fill the Orioles' gaping hole at second base in the short term. Regular second baseman Brian Roberts is still on the disabled list with a hip injury, and Robert Andino was placed on the DL with a shoulder injury on Monday. In the long term, though, Showalter said Quintanilla is capable of filling in anywhere in the infield.
"I see how we're going to use him," Showalter said, "but tomorrow would probably be a better time to talk about that. I have some ideas about how we're gonna use him."