Castillo signed a minor league deal with the Yankees on Saturday, Jon Heyman of MLB Network reports.
The veteran catcher spent last season in the Blue Jays' organization, slashing .250/.250/.344 at Triple-A Buffalo over 10 games. He figures to add depth at either Double-A Trenton or Triple-A Scranton/Wilkes-Barre, but a 32-year-old catcher that hasn't played at the major league level since 2009 is unlikely to crack the Yankees' 25-man roster.