Last week, Santana made his first start since tearing his Achilles tendon in June. He threw two perfect innings for Venezuelan winter league team Navegantes del Magallanes.
An MRI on his shoulder reportedly showed no structural damage, but Santana will miss the league final.
Santana, who has not pitched in the majors since 2012, will turn 36 in March. The veteran left-hander missed the 2011 and 2013 seasons with shoulder injuries, and then he sat out the 2014 season after tearing his Achilles last June during extended spring training with the Baltimore Orioles.
Prior to the most recent injury, Santana expected to sign with an MLB team before spring training.
Santana won Cy Young Awards with the Minnesota Twins in both 2004 and 2006. He was traded to the New York Mets in 2008 and signed a six-year, $137.5 million contract. In 2012, he threw the only no-hitter in Mets history before a back injury ended his season.
Over his 12 MLB seasons, Santana has posted a 139-78 record and a 3.20 ERA.
- Mike Fiammetta