General manager Alex Anthopoulos said Saturday that a toe infection was the primary factor in Santana's decision. He said Santana plans on pitching winter ball.
Santana hasn't pitched in the majors since 2012 with the New York Mets. The 36-year-old lefty signed a minor league deal with Toronto in February but never appeared in a game at any level.
He missed all of 2011 and 2013 following shoulder surgeries. He signed a minor league deal with Baltimore in 2014 but his season ended last June after he tore his Achilles tendon.
Santana is 139-78 with a 3.20 ERA in 12 major league seasons. He was the AL Cy Young winner with Minnesota in 2004 and 2006.