Outfield prospects L.J. Hoes and Xavier Avery, who both spent last season with Double-A Bowie, have also received invitations to big league Spring Training.
Ayala, 34, has spent seven seasons in the Majors, and he was 2-2 with a 2.09 ERA in 52 appearances for the Yankees last season. The right-hander had an ERA above 5.00 in 2008 and '09 -- a span in which he pitched for four different teams -- and did not pitch in the big leagues in 2010. But Ayala's success with the Yankees last year prompted multiple clubs to show interest in him this winter, and he will compete for a back-end job in Baltimore's bullpen.
Ayala, along with new acquisition Matt Lindstrom, could be used as setup man to Jim Johnson, who is all but assured the closer's role, given Kevin Gregg's struggles last season. The Orioles have ideally wanted to slot Lindstrom in the seventh inning, and are hoping to find an arm to handle the eighth and bridge to Johnson.
Nick Johnson will add depth at the first-base position, while Sardinha will do the same at catcher. Given the Orioles' wealth of pitching additions, the team will need several catchers at big league camp, and Sardinha -- who is more of a long shot to make the club -- figures to compete for a spot at Triple-A.
To clear room for Ayala on the 40-man roster, outfielder Matt Angle was designated for assignment. The 26-year-old Angle batted .271/.347/.344 in 108 games for Triple-A Norfolk in 2011 before joining the Orioles for 31 games.
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.