David Ortiz, 'Johnny Damon Picks Yanks Over Sox? That's Some Bulls**t!'

David Ortiz is just as surprised as the rest of us by his old teammate, Johnny Damon -- telling TMZ Sports he's SHOCKED that Damon would root for the Yankees to beat the Red Sox in the ALDS.

"Johnny Damon?! That's some bullsh*t, isn't it! Red Sox all the way," Big Papi told us.

Damon and Ortiz were both a part of that special 2004 "bunch of idiots" team who broke the Red Sox curse and won their first World Series since 1918. Damon left Boston in 2005 and signed a contract with the rival Yanks.

So, when we asked Johnny who he was pulling for now that his 2 former squads are facing off in the American League Division Series ... and he went with the Bronx Bombers.

Remember, there was bitterness between Damon and Boston -- and in 2015, Damon said he wasn't on speaking terms with Red Sox owner John Henry.

Still, Ortiz clearly felt like there was enough Beantown love for Damon to pick the Sox over the Yanks.